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| [[Image:Polywell WB-6 complete.jpg|thumb|Polywell WB-6 model assembled]]
| | I would like to introduce myself to you, I am Andrew and my wife doesn't like it at all. Playing badminton is a thing that he is completely addicted to. Some time ago she selected to live in Alaska and her parents live close by. Distributing production is where her primary income arrives from.<br><br>Also visit my site; [http://www.octionx.sinfauganda.co.ug/node/22469 tarot readings] |
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| A '''polywell''' is a type of [[fusion reactor]] that uses an electric field to do [[Work (physics)|work]] on ions, to heat them to fusion conditions. It traps [[electrons]] using [[magnetic confinement]]. The negatively charged electrons then attract positively charged [[ions]]. This accelerates the ions. If the ions collide at high speeds in the center, they can fuse. This is a form of [[Inertial electrostatic confinement|inertial electrostatic fusion]] and is closely related to the [[fusor]], [[magnetic mirror]]s and the [[biconic cusp]].
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| The polywell was developed by [[Robert Bussard]] as an improvement over the [[fusor]] it uses a negative plasma instead of a negative wire cage to attract ions. Dr. Bussard theorized that a polywell could potentially produce net energy. His company developed the initial devices for the [[United States Navy|U.S. Navy]]. The name polywell is a [[portmanteau]] of "[[polyhedron]]" and "[[potential well]]."
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| {{toclimit|3}}
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| == Description ==
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| A polywell consists of several parts. A set of positively charged [[electromagnet]] coils that are arranged in a [[polyhedron]]. This is called the MaGrid. This structure generates magnetic fields which are designed to trap electrons. The MaGrid is placed inside a wire cage within a vacuum chamber. Electrons are introduced into the cage and are accelerated towards the MaGrid using an electric field. Once inside the MaGrid, the electrons are confined by the magnetic fields. Those that escape are retained by the electric field. This configuration traps the electrons in the middle of the device. The electrons act as a virtual [[cathode]] (negative [[electric potential]]).
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| Gas is puffed into the cage. The gas ionizes when it reaches the electron cloud. The electron cloud generates a potential well. Ions fall down this well building up speed, slamming together and fusing in the center. Ions are also electrostatically confined so densely that they fuse, releasing energy. The energy required to confine the electrons is far smaller than that required to directly confine ions, as is done in other fusion projects such as [[ITER]].
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| == Development ==
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| === Fusor ===
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| [[File:Homemade fusion reactor.JPG|thumbnail|A homemade fusor built by a high school student in 2010]]
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| [[File:Fusor running.jpg|thumbnail|Farnsworth–Hirsch fusor during operation in so called "star mode" characterized by "rays" of glowing plasma which appear to emanate from the gaps in the inner grid.]]
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| [[File:Taylor Wilson Presenting Fusor to Obama.jpg|thumbnail|Taylor Wilson presenting fusor work to Barack Obama, 2/7/2012]]
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| A Farnsworth-Hirsch [[fusor]] consists of two wire cages, one inside the other. These are often referred to as grids. This structure is placed inside a [[vacuum]] chamber. The outer cage is charged positively against the inner cage. [[Atomic nucleus|nuclei]] are injected as [[ion]]s into the system. The most common fuel used is ionized [[deuterium]] gas. Because the ions are positive they fly towards the negative inner cage. If they miss the inner cage, they will fly right through the center of the device at high speeds. They can fly out the other side of the inner cage. As the ions move outward, they feel a [[Lorentz force]] which directs them back towards the center. Over time, a core of ionized gas can form inside the inner cage. They continue to pass back and forth through the core until they strike either the grid or another nucleus. Most strikes with other nuclei do not result in fusion, but occasionally the strikes are sufficiently energetic that fusion results. Grid strikes raise the temperature of the grid and lower the energy of the plasma.
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| A benefit of a [[fusor]] is that it loses very little energy as light; it has low [[radiation]] losses. The device has no magnetic fields, which means there are no [[synchrotron radiation|synchrotron losses]]. If the grid is kept cool, there is only a small amount of [[thermionic emission]]. Finally, if the grid is kept cool there is also a small amount of [[bremsstrahlung|x-ray]] radiation.<ref>{{cite web |title= Design Of An Actively Cooled Grid System To Improve Efficiency In Inertial Electrostatic Confinement Fusion Reactors |author= Andrew Seltzman |date= 2008-05-30 |work= www.rtftechnologies.org |url=http://www.rtftechnologies.org/Design/Assets/device-images/fusor-mark3/files/seltzman_andrew_h_200805_phys.pdf |accessdate= 2009-08-14
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| }}</ref>
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| The fundamental problem with a [[fusor]] is with the grid itself. Far too often, nuclei strike the grid. This is a [[Electrical conductor|conduction]] loss: the energy leaves with the mass leaving the machine. This reduces the [[fusor]]'s ability to generate power, by wasting the energy that went into ionizing and accelerating the particle. It also cools the plasma down and damages the grid. Even if the cooling problem was not critical, in a fusor scaled to power to a power plant, the fine mesh grid would overheat to the point of being vaporized.
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| === Elmore-Tuck-Watson ===
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| An Elmore-Tuck-Watson (ETW) [[fusor]] inverts the charge on the grids. It consists of a [[vacuum]] chamber containing a negatively charged outer grid (which may be the chamber) and a positively charged inner grid. Electrons (instead of ions) are injected into the system and accelerated toward the inner grid. As with normal [[fusor]]s, the particles move back and forth through the inner grid and core. As they pass repeatedly through the core, they generate a negatively charged zone, a potential well, which is called a virtual cathode. Fusible atomic [[Atomic nucleus|nuclei]] are then introduced inside the inner (positive) grid where they are ionized. The virtual cathode (electron cloud) accelerates the ions toward the center where they oscillate within the potential well. Since the ions never (in theory) reach the grid, they never lose their energy to impacts and continue to oscillate through the core. Given enough oscillations, the ions strike other high-energy ions and fuse.
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| This configuration avoids the [[Electrical conductor|conduction]] losses related to ions striking the inner negative grid. However, the fundamental problem with this system is still the grid itself. Far too often the ''electrons'' strike the grid, causing energy loss.
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| === Polywell ===
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| [[File:Polywell Magnetic Field.jpg|thumbnail|A plot of the magnetic field generated by the MaGrid inside a polywell. The null point is marked in red in the center.]]
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| The polywell generates the negative voltage needed to accelerate the [[ions]] using a cloud of net [[electrons]]. The extra electrons in the center form a virtual cathode, which ideally behaves like the [[fusor]]'s negative inner cage. This generates the electric field needed to accelerate ions to fusion conditions. The electrons forming this virtual cathode are confined using the [[magnetic mirror]] effect. Electrons are reflected from the dense magnetic fields at the corners of the rings. This design (in theory) avoids both types of losses; preventing both electrons and ions from hitting the grid. Ions are added, but an excess of electrons are kept to maintain the negative potential well.<ref name="patent1992">{{US patent reference|
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| number=5,160,695|y=1992|m=11|d=03|inventor=Robert W. Bussard|title= Method and apparatus for creating and controlling nuclear fusion reactions}}</ref>
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| The polywell differs from traditional magnetic confinement because the fields confines light electrons, which is much easier than containing the much heavier ions.<ref name="quasi">{{cite doi|10.1063/1.871103}}{{cite journal
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| |last= Krall | first = Nicholas A.
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| |coauthors= Bussard, Robert W.
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| |title= Forming and maintaining a potential well in a quasispherical magnetic trap
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| |journal= Physics of Plasmas
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| |volume= 2
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| |issue= 1
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| |year= 1995
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| |pages= 146–158
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| |doi= 10.1063/1.871103
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| |issn= 1070-664X |id=Forming_and_maintaining_a_potential_well_Krall_Bussard_1995.pdf
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| |bibcode = 1995PhPl....2..146K }}</ref><ref name="tech">{{cite journal
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| |last= Bussard | first = Robert W.
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| |title= Some physics considerations of magnetic inertial-electrostatic confinement; A new concept for spherical converging-flow fusion
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| |journal= Fusion Technology
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| |volume= 19
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| |issue= 2
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| |year= 1991
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| |pages= 273–293
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| |issn= 07481896 |id=Some_physical_Considerations_Bussard_FusionTechnology_1991.pdf
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| }}</ref><ref name="tech2">{{cite journal
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| |last= Krall | first = Nicholas A.
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| |title= The Polywell; A spherically convergent ion focus concept
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| |journal= Fusion Technology
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| |volume= 22
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| |issue= 1
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| |year= 1992
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| |pages= 42–49
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| |issn= 07481896 |id=Polywell_spherically_convergent_ion_focus_concept_Fusion_Technology_Krall_1992.pdf
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| }}</ref>
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| Most experiments use six rings in a square. This is referred to as the MaGrid. Each ring is a discrete, circular coil of wire inside a smooth shell. All the magnetic flux that enters the volume through the coils leaves it again through the spaces between the coils. These are [[electromagnets]], each with a north and south pole. All poles are pointing toward (or all away from) the center. The magnetic field vanishes at the center by symmetry, creating a null point. Single electrons travel straight through the null point, due to their infinite [[gyroradius]] in regions of no magnetic field. As they head to the corners they experience a [[Lorentz force]] which causes them to corkscrew tighter and tighter along the denser magnetic field lines.<ref name="Low beta confinement in a Polywell modeled with conventional point cusp theories">{{cite journal |last= Carr| first = Matthew|title= Low beta confinement in a Polywell modeled with conventional point cusp theories |journal= Physics of Plasma |volume= 18 |issue= 11 |year= 2011 |url=http://pop.aip.org/resource/1/phpaen/v18/i11/p112501_s1
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| }}</ref> Their [[gyroradius]] shrinks and when they hit a dense magnetic field they can be reflected using the [[magnetic mirror]] effect.<ref name="F. Chen 1984 pp. 30">{{cite book|first=F. |last=Chen |title=Introduction to Plasma Physics and Controlled Fusion |publisher=Plenum |location=New York |year=1984 |volume=1 |pages=30–34 |ISBN=978-0-306-41332-2}}</ref> This is typical of all [[Electron cyclotron resonance]] motion. This particle behavior is very similar to studies in the [[biconic cusp]] from the early 1960s.<ref name="ReferenceA">The motion of a charged particle near a zero field point (in english). New York: New York University: Courant Institute of Mathematical Sciences,. 1961</ref> This configuration and motion can confine electrons and ions inside the center of the rings. Ideally, the plasma would be electron rich to create the negative voltage drop. Bussard claimed that the MaGrid arrangement of the magnetic field has only point [[cusp]]s{{disambiguation needed|date=December 2013}} but acknowledged that the circular coils produce line-like cusps at the closest approaches of the coils.<ref name="patent1989">{{US patent reference|
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| number=4,826,646|
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| y=1989|m=05|d=02|
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| inventor=Robert W. Bussard|
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| title= Method and apparatus for controlling charged particles}}</ref>
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| ==== Results ====
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| Despite initial difficulties in spherical electron confinement, at the time of the 2005 research project's termination, Bussard reported a fusion rate of 10<sup>9</sup> per second running D-D fusion reactions at only 12.5 kV (based on [[neutron detection|detecting]] a total of nine neutrons in five tests,<ref name="IAC2006">[http://www.askmar.com/ConferenceNotes/2006-9%20IAC%20Paper.pdf "The Advent of Clean Nuclear Fusion: Super-performance Space Power and Propulsion"], Robert W. Bussard, Ph.D., 57th International Astronautical Congress, October 2–6, 2006</ref><ref name="lab_notes">''Final Successful Tests of WB-6'', EMC2 Report, currently (July 2008) not publicly available<!-- {{
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| cite web
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| |title= Final Successful Tests of WB-6
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| |author= EMC2 Report
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| |url= http://ecow.engr.wisc.edu/cgi-bin/getbig/ne/527/anderson/notes/bussard_wb6rpt080604fnl0107.pdf
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| |accessdate= 2007-11-08
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| }} --></ref> giving a wide [[confidence interval]]). He stated that the fusion rate achieved by WB-6 was roughly 100,000 times greater than what Farnsworth achieved at similar well depth and drive conditions.<ref name="fusor.net">{{cite web
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| |title= Inertial Electrostatic Fusion systems can now be built
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| |author= Robert W. Bussard
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| |date= 2006-03-29
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| |work= fusor.net forums
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| |url= http://www.fusor.net/board/view.php?site=fusor&bn=fusor_announce&key=1143684406
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| |accessdate=2006-12-03
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| }}</ref><ref name="randi">{{cite web
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| |title= Fusion, eh?
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| |author= SirPhilip (posting an e-mail from "RW Bussard")
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| |date= 2006-06-23
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| |work= [[James Randi Educational Foundation]] forums
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| |url= http://forums.randi.org/showthread.php?t=58665#27
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| |accessdate=2006-12-03
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| }}</ref> By comparison, researchers at the [[University of Wisconsin–Madison]] reported a neutron rate of up to 5×10<sup>9</sup> per second at voltages of 120 kV with an electrostatic fusor without magnetic fields.<ref>{{cite web|url=http://iec.neep.wisc.edu/results.php |title=Inertial Electrostatic Confinement Project - University of Wisconsin - Madison |publisher=Iec.neep.wisc.edu |date= |accessdate=2013-06-17}}</ref>
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| Bussard asserted, by using [[superconductor]] coils, the only significant energy loss channel is through electron losses proportional to the surface area. He also stated that the density would scale with the square of the field (constant [[Beta (plasma physics)|beta]] conditions), and the maximum attainable magnetic field would scale with the radius (technological constraints). Under those conditions, the fusion power produced would scale with [[Power law|the seventh power of]] the radius, and the energy gain would scale with the fifth power. While Bussard did not publicly document the physical reasoning underlying this estimate,<ref>
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| Possibly he assumed that the ion energy distribution is fixed, that the magnetic field scales with the linear size, and that the ion pressure (proportional to density) scales with the [[magnetic pressure]] (proportional to ''B''²). The ''R''<sup>7</sup> scaling results from multiplying the fusion power density (proportional to density squared, or ''B''<sup>4</sup>) with the volume (proportional to''R''³). On the other hand, if it is important to maintain the ratio of the [[Debye length]] or the [[gyroradius]] to the machine size, then the magnetic field strength would have to scale ''inversely'' with the radius, so that the total power output would actually be lower in a larger machine.</ref> if true, it would enable a model only ten times larger to be useful as a fusion power plant.<ref name="IAC2006"/>
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| == Behavior ==
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| [[File:Single Electron Motion Illustration.jpg|thumbnail|default|This is an illustration of single electron motion inside the polywell. It is based on figures from “Low beta confinement in a polywell modeled with conventional point cusp theories” but is not an exact copy.]]
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| === Single electron motion ===
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| [[Particle-in-cell]] simulations of the polywell have shown electron motion.<ref name="Low beta confinement in a Polywell modeled with conventional point cusp theories"/> Free electrons are [[thermionic emission|released]] outside the rings. They are subject to the surrounding [[lorentz force|electric field]] pulling them into the center.<ref name="google"/> As they accelerate, their [[kinetic energy]] rises. They begin to be affected by the magnetic field. Ideally, the magnetic overtakes the electric [[lorentz force]] and the electron start corkscrewing. This is known as [[electron cyclotron resonance]] motion. Electrons corkscrew around the magnetic field lines, spinning in a tighter orbit in denser fields. The radius of this motion is known as the [[gyroradius]].<ref name="F. Chen 1984 pp. 30"/> They enter the ring structure in a tight corkscrew, which widens as they move into the center. In the center there is a [[Null (physics)|null point]], a region of no magnetic field.<ref name="Low beta confinement in a Polywell modeled with conventional point cusp theories"/> Single electrons travel straight through this [[Null (physics)|null point]], due to their infinite [[gyroradius]] in regions of no magnetic field.<ref name="autogenerated1995"/> This straight motion can scatter the electrons.<ref name="Low beta confinement in a Polywell modeled with conventional point cusp theories"/> Next, the electrons head towards the cusps at the corners or sides of the rings.<ref name="Low beta confinement in a Polywell modeled with conventional point cusp theories"/><ref name="Oct12013Paper">"Scaling law of electron confinement in a zero beta polywell device" Devid Gummershall, Matthew Carr, Scott Cornish, Physics of Plasma 20, 102701 (2013)</ref> They enter regions with denser and denser magnetic fields, causing their gyroradius to shrink. Ideally, they are reflected back into the center using the [[magnetic mirror]] effect.<ref name="F. Chen 1984 pp. 30"/><ref name="P Chernnin 1978">"ion losses from end-stoppered mirror trap" D P Chernnin, nuclear fusion 18 (1978)</ref> This particle behavior is very similar to studies of the [[biconic cusp]] from the early 1960s.<ref name="ReferenceA">The motion of a charged particle near a zero field point (in english). New York: New York University: Courant Institute of Mathematical Sciences, 1961</ref> As the particle changes speed, it radiates energy as light. This radiation is a way that the machine can lose energy. Radiation increases as the plasma gets hotter. This can be calculated using the [[Larmor formula]] <ref>Jackson, John D. (1998). Classical Electrodynamics (3rd ed.). Wiley. ISBN 0-471-30932-X.</ref>
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| A visualization of particle motion in polywell has been made in 3D simulations by Indrek Mare <ref>{{youtube|id=ao0Erhsnor4 |Polywell simulation 3D}}</ref> and by John Coady.
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| === Ion confinement ===
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| Ideally, the polywell confines the [[ion]]s and [[electron]]s through two different means, borrowed from [[fusor]]s and [[magnetic mirror]]s. The electrons are easier to confine magnetically because they have so much less mass than the ions.<ref>"Biased probe analysis of potential well formation in an electron only, low beta Polywell magnetic field" Physics of Plasma, May 9, 2013, Volume 20, 052504</ref>
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| The machine confines ions using an [[electric field]] in the same way a fusor confines the ions. In the polywell, the ions are attracted to the negative cloud in the center. In the fusor, they are attracted to a negative wire cage in the center. This is the same method used for all [[inertial electrostatic confinement]] devices. Both concepts intend to operate with a highly [[Nonthermal plasma]], ideally mono-energetic, distribution of ion energies.<ref name="tech" /> If the ion energies can be held near the optimum value, the fusion rate for a given plasma pressure can be a few times higher than the maximum rate possible for ions with a thermal distribution. On the other hand, collisions and collective instabilities have a tendency to restore a thermal distribution, so that it generally costs power to maintain a mono-energetic distribution.
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| === Electron confinement ===
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| The machine traps the electrons inside the rings using magnetic fields, the same way the [[Magnetic mirror]] machines and [[biconic cusp]] concept traps them.<ref name="P Chernnin 1978"/><ref>The motion of a charged particle near a zero field point (in english). New York: New York University: Courant Institute of Mathematical Sciences,. 1961.</ref> These magnetic fields will also simultaneously affect the ions. When a charged particle enters a dense magnetic field it feels a repulsive force reflecting it back to a lower density field.<ref>F. Chen, Introduction to Plasma Physics and Controlled Fusion (Plenum, New York, 1984), Vol. 1, pp. 30–34. ISBN 978-0-306-41332-2</ref> This is the magnetic mirror effect. This has been used in several [[magnetic confinement fusion]] schemes to trap charged particles.
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| The polywell uses the [[Magnetic mirror|mirror]] effect every time a charged particle moves from a low density to a high density magnetic field. The charged particle is reflected back to the low density field. Ideally, the machine is set up so that the lowest density field (the null point) is in the center.<ref>"Forming and maintaining a potential well in a quasi spherical magnetic trap" Nicholas Krall, M Coleman, K Maffei, J Loveberg, R Jacobsen, R Bussard, Physics of Plasma, Vol 2, 1, January 1995</ref> This means that electrons are reflected and trapped internally by the mirror effect. This is a very similar design to the biconic cusp. In several configurations, this magnetic containment is boosted by adding an outside electric field.<ref name="google"/> If the electron escapes the rings, it is attracted back to the positive rings.
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| This machine also shares a similarity with magnetic mirrors in that they both attempt to confine a non-thermal distribution of electron energies (a [[Nonthermal plasma]]). In some mirror configurations, the field in the center is a minimum in every direction, as it is in the central region of a polywell. The magnetic field in such a case is said to have "good curvature" because a certain class of fluctuations are stable in a plasma contained by such a field {{Citation needed|date=January 2014}}.
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| == Considerations for net power ==
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| === Fuel type ===
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| [[File:Fusion rxnrate.svg|thumbnail|This is a plot of the cross section of different fusion reactions.]]
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| [[Nuclear fusion]] refers to reactions in which lighter [[atomic nucleus|nuclei]] are combined to become heavier nuclei. This process changes [[Mass–energy equivalence|mass into energy]] which may be captured to provide [[fusion power]]. Many types of atoms can be fused. The [[probability]] of a fusion reaction occurring is controlled by the [[cross section (physics)|cross section]] of the fuel,<ref>"Development of the indirect drive approach to inertial confinement fusion and the target physics basis for ignition and gain" John Lindl, Physics of Plasma, 1995</ref> which is in turn a function of its temperature. The easiest nuclei to fuse are [[deuterium]] and [[tritium]], and their fusion occurs when the ions have a temperature of at least 4 keV ([[kiloelectronvolt]]s) or about 45 million [[Kelvin]]. The polywell would achieve this by accelerating an ion with a charge of [[Elementary charge|1]] down a 4,000 volt electric field. The high cost, short [[half-life]] and [[radioactive|radioactivity]] of [[tritium]] made it difficult to be used by Bussard's team. The second easiest reaction is to fuse [[deuterium]] with itself. Because of its low cost, [[deuterium]] is commonly used by [[Fusor]] amateurs, and Bussard's polywell experiments were performed using this fuel. Any fusion reaction using [[deuterium]] or [[tritium]] will produce a fast neutron and is therefore radioactive. Dr. Bussard's goal was to fuse [[boron| boron-11]] with protons; this is a fusion reaction which is [[Aneutronic fusion|aneutronic]] (does not produce neutrons).
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| === Lawson criterion ===
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| At such conditions, the atoms are ionized and make a [[plasma (physics)|plasma]]. The energy generated by fusion, inside a hot plasma cloud can be found with the following equation.<ref name = "Lawson">"Some Criteria for a Power producing thermonuclear reactor" John Lawson, Atomic Energy Research Establishment, Hanvell, Berks, 2nd November 1956</ref>
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| :<math>P_\text{fusion} = n_A n_B \langle \sigma v_{A,B} \rangle E_\text{fusion}</math>
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| where:
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| * <math>P_\text{fusion}</math> is the fusion power density (energy per time per volume),
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| * ''n'' is the number density of species A or B (particles per volume),
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| * <math>\langle \sigma v_{A,B} \rangle</math> is the product of the collision cross-section ''σ'' (which depends on the relative velocity) and the relative velocity of the two species ''v'', averaged over all the particle velocities in the system.
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| This equation shows that energy varies with the temperature, density, speed of collision, and fuel used. To reach net power, fusion reactions have to occur fast enough to make up for energy losses. Any power plant using fusion will hold in this hot cloud. Plasma clouds lose energy through [[Thermal conduction|conduction]] and [[radiation]].<ref name = "Lawson"/> Conduction is when [[ion]]s, [[electron]]s or [[neutral particle|neutrals]] touch a surface and leak out. Energy is lost with the particle. Radiation is when energy leaves the cloud as light. Radiation increases as the temperature rises. To get net power from fusion, you must overcome these losses. This leads to an equation for power output (where: ''η'' is machine efficiency).
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| :<math>P_\text{out} = \eta_\text{capture}\left(P_\text{fusion} - P_\text{conduction} - P_\text{radiation}\right)</math>
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| John Lawson used this equation to estimate some conditions for net power <ref name = "Lawson"/> based on a [[Maxwell–Boltzmann distribution|Maxwellian]] cloud.<ref name = "Lawson"/> This is the [[Lawson criterion]].
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| === Criticism ===
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| In his thesis<ref name = "Rider95Paper">[http://dspace.mit.edu/bitstream/1721.1/11412/1/33227017.pdf ''Fundamental limitations on fusion systems not in equilibrium'', pp. 161-2]</ref> and his 1995 publication,<ref>“A general critique of internal-electrostatic confinement fusion systems” Plasma Physics, June 1995, Dr. Todd Rider, MIT</ref> [[Massachusetts Institute of Technology|MIT]] doctoral student Todd Rider had calculated that [[bremsstrahlung|x-ray radiation]] losses with this fuel will exceed fusion power production by at least 20%. Rider modeled the system using the following assumptions:
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| * The plasma was [[Plasma (physics)|quasineutral]]. Therefore positives and negatives were equally mixed together.<ref name = "Rider95Paper"/>
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| * The fuel was evenly mixed throughout the volume.<ref name="Rider95Paper"/>
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| * The plasma was isotropic, meaning that its behavior was the same in any given direction.<ref name="Rider95Paper"/>
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| * The plasma had a uniform energy and temperature throughout the cloud.<ref name="Rider95Paper"/>
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| * The plasma was an unstructured Gaussian sphere, with a strongly converged dense central core. The core represented a small (~1%) part of the total volume.<ref name = "Rider95Paper"/> In a later 1995 paper, Dr. William Nevins at [[Los Alamos National Laboratory|LANL]] argued against this assumption. He argued that the particles would build up [[angular momentum]], causing the dense core to degrade.<ref = "Nevins95">Nevins, William M. "Can Inertial Electrostatic Confinement Work beyond the Ion-ion Collisional Time Scale?" Physics of Plasmas 2.10 (1995): 3804-819. Print.</ref> The loss of density inside the core would reduce fusion rates.
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| * The potential well was broad and flat.<ref name="Rider95Paper"/>
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| Based on these assumptions, Rider used general equations<ref>Lyman J Spitzer, "The Physics of Fully Ionized Gases" 1963</ref> to estimate the rates of different physical effects. These included, but were not limited to, the loss of ions to up-scattering, the ion thermalization rate, the energy loss due to [[Bremsstrahlung|x-ray radiation]] and the fusion rate.<ref name="Rider95Paper"/> His conclusions were that the device suffered from "fundamental flaws".<ref name="Rider95Paper"/>
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| By contrast, Bussard has argued <ref name="IAC2006"/> that the plasma inside the polywell has different structure, temperature distribution and well profile. These characteristics have not been fully measured and are central to the devices feasibility. Based on this his calculations indicate that the bremsstrahlung losses would be much smaller.<ref name="looses">[http://www.askmar.com/Fusion_files/EMC2%20Reports EMC2-0891-04%201991%20Bremmstrahlung%20Radiation%20Losses.pdf "Bremsstrahlung Radiation Losses in Polywell Systems"], R.W. Bussard and K.E. King, EMC2, Technical Report EMC2-0891-04, July, 1991. Table 2, p. 6.</ref> According to Bussard the high speed and therefore low cross section for [[Coulomb collision]]s of the ions in the core makes [[thermalisation|thermalizing]] collisions very unlikely, while the low speed at the rim means that thermalization there has almost no impact on ion velocity in the core.<ref name="IAC2006"/> Bussard calculated that a polywell reactor with a radius of 1.5 meters would produce net power fusing [[deuterium]].<ref>[https://n3172061.readyexchange.net/lampoil/Fusor/Shared%20Documents/SGCPolywell.pdf ''Safe, Green, Clean - the p-B Polywell: A Different Kind of Nuclear .'', pp. 66]</ref>
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| === Energy capture ===
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| It has been proposed that energy may be extracted in polywells using [[Rankine cycle|heat capture]] or [[direct conversion]] though that scheme will have general challenges.<ref>"Generic issues for direct conversion of fusion energy from alternative fuels" Marshall N Rosenbluth and F L Hinton, Plasma Phys. Control. Fusion 36 (1994) 1255-1268</ref>
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| == History ==
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| [[Image:Polywell WB-2.jpg|thumb|WB-2]]
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| [[Image:Polywell WB-3.jpg|thumb|WB-3]]
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| [[Image:Polywell WB-6 coils.jpg|thumb|WB-6 during assembly with coils showing]]
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| In the late 1960s there were several investigations of polyhedral magnetic fields as a possibility to confine a fusion plasma.<ref>R.Keller and I.R.Jones, "Confinement d'un Plasma par un Systemem Polyedrique a' Courant Alternatif", ''Z. Naturforschung'', Vol. 21 n, pp. 1085-1089 (1966), as cited by R.W.Bussard in U.S.Patent 4,826,646, "Method and apparatus for controlling charged particles", issued May 2, 1989, p.12.</ref><ref>"Spherical Multipole Magnets for Plasma Research", Sadowsky, M., ''Rev.Sci.Instrum.'' 40 (1969) 1545</ref> The first proposal to combine this magnetic configuration with an electrostatic potential well in order to improve electron confinement was made by [[Lavrentiev, Oleg|Lavrentiev]] in 1975.<ref>"Electrostatic and Electromagnetic High-Temperature Plasma Traps", O.A.Lavrent’ev, Conference Proceedings, Electrostatic and Electromagnetic Confinement of Plasmas and the Phenomenology of Relativistic Electron Beams, ''Ann. N.Y. Acad. Sci.'' 251, (1975) 152-178, as cited by Todd H. Rider in "A general critique of inertial-electrostatic confinement fusion systems", ''Phys. Plasmas'' 2 (6), June 1995. Rider specifically stated that "Bussard has revived an idea originally suggested
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| by Lavrent’ev".</ref> The idea was picked up by [[Robert Bussard]] in 1983, a link acknowledged in the references cited by his 1989 patent application,<ref name="patent1989" /> though in 2006 he appears to claim to have re-discovered the idea independently.<ref name="quick">{{cite web
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| |url= http://www.fusor.net/board/getfile.php?bn=fusor_announce&att_id=2494
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| |title= A quick history of the EMC2 Polywell IEF concept
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| |author= Posted to the web by Robert W. Bussard
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| |accessdate= 2006-12-03
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| |date=February 2006
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| |format= [[Microsoft Word]] document
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| |publisher= Energy/Matter Conversion Corporation
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| }}</ref>
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| === HEPS ===
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| Research was funded first by the [[Defense Threat Reduction Agency]] beginning in 1987 and later by [[DARPA]].<ref name=google/>{{rp|32:30}} This funding resulted in a first machine known as the high energy power source (HEPS) experiment. This was built by Directed Technologies Inc in San Diego.<ref name="autogenerated1995">"Forming and maintaining a potential well in a quasispherical magnetic trap" Nicholas Krall, M Coleman, K Maffei, J Lovberg Physics of Plasma 2 (1), 1995</ref> This machine was a large (190 cm across) machine, where the rings were placed outside of the vacuum chamber.<ref name=google/>{{rp|32:33}} This machine performed poorly because the [[magnetic field]]s sent [[electron]]s into the walls, driving up conduction losses. At the time, these losses were thought to be due to poor electron injection.<ref name="autogenerated1995"/> The [[United States Navy]] began providing low-level funding to the project in 1992.<ref name="clean">{{cite web
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| |url= http://www.fusor.net/board/getfile.php?bn=fusor_announce&att_id=2493
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| |title= Inertial electrostatic fusion (IEF): A clean energy future
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| |author= Posted to the web by Robert W. Bussard
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| |accessdate= 2006-12-03
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| |format= [[Microsoft Word]] document
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| |publisher= Energy/Matter Conversion Corporation
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| }}</ref> Results from the HEPS program were published by Dr. [[Nicholas Krall]] in 1994.<ref name="autogenerated1995"/>
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| Bussard, who had been an advocate for [[Tokamak]] research, became the advocate for this concept, so that the idea is now indelibly associated with his name. In 1995 he sent a letter to the [[United States Congress]] stating that he had only supported Tokamaks in order to get fusion research sponsored by the government, but he now believed that there are better alternatives to Tokamaks.
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| === EMC inc ===
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| [[Robert Bussard]] founded EMCC incorporated in 1987 <ref name="google"/> and after the HEPS program ended, the company took on the research. Successive machines were made, starting from WB-1 to WB-8. The company won an [[SBIR]] I grant in 92-93 and an [[SBIR]] II grant in 94-95, both from the US Navy.<ref name="quick" >"A QUICK HISTORY OF THE EMC2 POLYWELL IEF CONCEPT", EMC inc. 2006</ref> In 1993, it received a grant from the [[Electric Power Research Institute]] to examine the use of this machine in power production.<ref name="quick"/> In 1994, The company received small grants from [[NASA]] and [[LANL]].<ref name="quick"/> Starting in 1999, the company was primarily funded by the US Navy.<ref name="quick"/>
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| One early design was WB-1, which had six conventional [[magnet]]s in a cube. This device was 10 cm across.<ref name="quick"/> This was followed by WB-2, which used coils of wires to generate the magnetic field. Each [[electromagnet]] had a square cross section, which created problems. The [[magnetic]] fields drove electrons into the metal rings raising conduction losses and affects electron trapping. This design also suffered from "funny cusp" losses at the joints between magnets. The WB-6 machine attempted to address these problems, by using circular rings and spacing them some distance apart.<ref name="google"/> The next device, PXL-1, was built in 1996 and 1997. This machine was 26 cm across and used flatter rings to generate the field.<ref name="quick"/> From 1998 to 2005 the company built a succession of six machines: WB-3, MPG-1,2, WB-4, PZLx-1, MPG-4 and WB-5. All of these reactors were six magnet designs built as a cube or [[truncated cube]]. They ranged from 3 to 40 cm in radius.<ref name="quick"/>
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| === WB-6 ===
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| Funding became tighter and tighter. According to [[Bussard]], "The funds were clearly needed for the more important [[2003 Invasion of Iraq|War in Iraq]]."<ref name="randi"/> An extra $900k of [[Office of Naval Research]] funding allowed the program to continue long enough to reach WB-6 testing in November 2005. The WB-6 machine had rings with circular cross sections that space apart at the joints. This reduced the metal surface area unprotected by magnetic fields. These changes dramatically improved system performance, leading to more electron recirculation and better confinement of electrons, in a progressively tighter core. This machine produced a fusion rate of 10<sup>9</sup> per second. This is based on a total of nine neutrons in five tests, giving a wide confidence interval.<ref name="IAC2006"/><ref name="lab_notes"/> Drive voltage on the WB-6 tests was about 12.5 kV, with a resulting potential well depth of about 10 kV.<ref name="IAC2006"/> Thus deuterium ions could have a maximum of 10 keV of kinetic energy in the center. By comparison, a [[Fusor]] running deuterium fusion at 10 kV would produce a fusion rate difficult to detect at all. [[Robert L. Hirsch]] reported a fusion rate this high only by driving his machine with a 150 kV drop between the inside and outside cages.<ref>Robert L. Hirsch, "Inertial-Electrostatic Confinement of Ionized Fusion Gases", Journal of Applied Physics, v. 38, no. 7, October 1967</ref> Hirsch also used [[deuterium]] and [[tritium]], a much easier fuel to fuse, because it has a higher [[nuclear cross section]].
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| While the pulses of operation in WB-6 were sub-milliseconds, Bussard felt the conditions should represent steady state as far as the physics are concerned. A last-minute test of WB-6 ended prematurely when the insulation on one of the hand-wound [[electromagnet]]s burned through, destroying the device.
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| === Efforts to restart funding ===
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| With no more funding during 2006, the project was stalled. This ended [[Robert Bussard#Appeal for funding|an 11 year embargo on publication and publicizing]] which the US Navy had in place from 1994 and 2005 <ref>There is this clause in the [https://www.neco.navy.mil/upload/N68936/N6893609R0024RFP.pdf "Solicitation, Offer and Award"] for the "plasma wiffleball development project", [https://www.fbo.gov/index?s=opportunity&mode=form&id=754cf58a3fd1b02abfe8521ff4f488a7&tab=core&_cview=1&cck=1&au=&ck= awarded] on March 3, 2009, to Matter Conversion Corporation:
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| <blockquote> | |
| 5252.204-9504 DISCLOSURE OF CONTRACT INFORMATION (NAVAIR) (JAN 2007)
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| (a) The Contractor shall not release to anyone outside the Contractor’s organization any unclassified information (e.g., announcement of contract award), regardless of medium (e.g., film, tape, document), pertaining to any part of this contract or any program related to this contract, unless the Contracting Officer has given prior written approval.
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| (b) Requests for approval shall identify the specific information to be released, the medium to be used, and the purpose for the release. The Contractor shall submit its request to the Contracting Officer at least ten (10) days before the proposed date for release.
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| (c) The Contractor agrees to include a similar requirement in each subcontract under this contract. Subcontractors shall submit requests for authorization to release through the prime contractor to the Contracting Officer.
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| </blockquote></ref> The company's military-owned equipment was transferred to [[SpaceDev]], which also hired three of the team's researchers.<ref name="randi"/> After the transfer, Bussard tried to attract new investors, giving talks trying to raise interest in his design. He gave a talk at [[Google]] headquarters had the title, "Should Google Go Nuclear?"<ref name="google">{{cite web |url= http://www.youtube.com/watch?v=FhL5VO2NStU |title= Should Google Go Nuclear? Clean, cheap, nuclear power (no, really) |author= Dr. Robert Bussard (lecturer) |accessdate= 2006-12-03 |date= 2006-11-09 |format= [[Adobe Flash|Flash]] video|work= Google Tech Talks |publisher= [[Google]]}}</ref> He also presented and published an overview of the work at the 57th [[International Astronautical Congress]] in October 2006.<ref name="IAC2006"/> He presented at an internal [[Yahoo!]] Tech Talk on April 10, 2007.<ref>[http://www.askmar.com/Fusion.html ''Askmar summary of IEC fusion'']</ref> and spoke on the internet talk radio show ''The Space Show'' on May 8, 2007. Dr. Bussard formed EMC2 Fusion Development Corporation,<ref>{{cite web|url=http://www.emc2fusion.org/ |archiveurl=http://web.archive.org/web/20120106154553/http://www.emc2fusion.org/ |archivedate=2012-01-06 |title=Emc2 Fusion Development Corporation |publisher=Web.archive.org |date= |accessdate=2013-06-17}}</ref> a [[non-profit organization]], to seek funding for continuation of the project. Bussard had plans for a WB-8 machine which was a higher-order polyhedron, with 12 electromagnets. However, this design was not used in the actual WB-8 machine.
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| Bussard believed that the WB-6 machine had demonstrated itself to the degree and that no intermediate-scale models would be needed, and noted, "We are probably the only people on the planet who know how to make a real net power clean fusion system"<ref name="fusor.net"/> He proposed to rebuild WB-6 more robustly to verify its performance. After publishing the results, he planned to convene a conference of experts in the field in an attempt to get them behind his design. The first step in that plan was to design and build two more small scale designs (WB-7 and WB-8) to determine which full scale machine would be best. He wrote “The only small scale machine work remaining, which can yet give further improvements in performance, is test of one or two WB-6-scale devices but with “square“ or polygonal coils aligned approximately (but slightly offset on the main faces) along the edges of the vertices of the polyhedron. If this is built around a [[truncated dodecahedron]], near-optimum performance is expected; about 3-5 times better than WB-6.” <ref name="IAC2006"/> [[Robert W. Bussard]] died in October 6th 2007 from [[multiple myeloma]] at the age of 79.<ref>{{cite web|title=''Dr. Robert W. Bussard Has Passed''|url=http://www.classicalvalues.com/archives/2007/10/dr_robert_w_bus.html|date=2007-10-08|accessdate=2007-10-09|work=Classical Values|author=M. Simon}}</ref>
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| In 2007, [[Stephen Chu]], [[Nobel Prize in Physics|Nobel laureate]] and former [[United States Secretary of Energy]], answered a question about polywell at a tech talk at [[Google]]. He said: "So far, there's not enough information so [that] I can give an evaluation of the probability that it might work or not...But I'm trying to get more information."<ref>{{cite web
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| |url= http://cosmiclog.msnbc.msn.com/archive/2008/12/16/1718741.aspx |title= Fusion we can believe in? |accessdate=2008-12-18|date=December 2008
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| |format= Science subsite of MSNBC.com |publisher= MSNBC.com}}</ref>
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| == Bridge funding 2007-2009 ==
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| === Reassembling team ===
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| In August 2007, EMC2 received a $1.8M U.S. Navy contract to continue the reactor development.<ref name="New Energy and Fuel">{{cite web |url= http://newenergyandfuel.com/http://newenergyandfuel/com/2007/08/23/funding-continues-for-bussards-fusion-reactor/ |title=Funding Continues for Bussard's Fusion Reactor|date= 2007-08-27| publisher = New Energy and Fuel}} Note that this source is a blog and not necessarily reliable.</ref> Before Bussard's death in October, 2007,<ref name="defencenews">{{cite web |url= http://www.defensenews.com/story.php?F=3139619&C=america |title= Fusion Researcher Bussard Dies at 79 |author=William Matthews |accessdate=2007-11-06|date= 2007-11-06 |format= webpage|work= Online article| publisher = Defencenews.com}}</ref> Dolly Gray, who co-founded EMC2 with Bussard and served as its president and CEO, helped assemble the small team of scientists in [[Santa Fe, New Mexico|Santa Fe]] to carry on his work. The group was led by Richard Nebel and included Princeton trained physicist Dr. Jaeyoung Park. Both physicists were on leave from the Los Alamos National Laboratory ([[LANL]]). The group also included Mike Wray, the physicist who ran the key 2005 tests; and Kevin Wray, who is the computer specialist for the operation.
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| === WB-7 ===
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| A more robust version of the WB-6 fusion device, was constructed at a machine shop in San Diego and shipped to Santa Fe to the EMC2 testing facility. The device was termed WB-7 and like prior ones, was designed by engineer Mike Skillicorn. This machine has a design similar to WB-6. WB-7, achieved "1st plasma" in early January, 2008.<ref name="MSNBC - CosmicLog">{{cite web |url= http://cosmiclog.msnbc.msn.com/archive/2008/01/09/566532.aspx |title=Strange Science Takes Time|date= 2008-01-09| publisher = MSNBC}}</ref><ref name="MSNBC - CosmicLog2">{{cite web |url= http://cosmiclog.msnbc.msn.com/archive/2008/06/12/1136887.aspx |title=Fusion Quest Goes Forward|date= 2008-06-12 |publisher= MSNBC}}</ref> In August 2008, the team finished the first phase of their experiment and submitted the results to a peer review board. Based on this review, federal funders agreed the team should proceed to the next phase. Dr. Nebel has said "we have had some success", referring to the team's effort to reproduce the promising results obtained by Dr. Bussard. "It's kind of a mix", Dr. Nebel reported. "We're generally happy with what we've been getting out of it, and we've learned a tremendous amount" he also said.<ref>{{cite web |url= http://cosmiclog.msnbc.msn.com/archive/2008/08/28/1301440.aspx?CommentPosted=true |title=Fusion effort in Flux |author=Posted to the web by Alan Boyle |accessdate=2008-09-08|date=September 2008 |publisher= MSNBC}}</ref>
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| === FY 2009 work ===
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| In September 2008 the [[Naval Air Warfare Center]], Weapons Division, [[Naval Air Weapons Station China Lake|China Lake, CA]] publicly pre-solicited a contract for research on an Electrostatic "[[Wiffle Ball]]" Fusion Device.<ref>{{cite web |url= https://www.fbo.gov/?tab=core&s=opportunity&mode=form&id=3ea62e93d6aa0220c884d316af43c00b |title= A—Fusion Device Research, Solicitation Number: N6893608T0283 |accessdate=2008-10-02 |date=September 2008 |publisher= Federal Business Opportunities }}</ref> In October 2008 the US Navy publicly pre-solicited two more contracts<ref>{{cite web |url= https://www.fbo.gov/?tab=core&s=opportunity&mode=form&id=80e8b7c1181e3e54d92a8d23e3eec700 |title= A—Polywell Fusion Device Research, Solicitation Number: N6893609T0011 |accessdate=2008-11-07 |date=October 2008 |publisher= Federal Business Opportunities}}</ref><ref>{{cite web |url= https://www.fbo.gov/?tab=core&s=opportunity&mode=form&id=8e59e11465cc26d4079ac9201008f960 |title= A—Spatially Resolved Plasma Densities/Particle Energies, Solicitation Number: N6893609T0019
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| |accessdate=2008-11-07 |date=October 2008 |publisher= Federal Business Opportunities}}</ref> also targeted toward EMC2 as preferred supplier. These two tasks were to develop better instrumentation and to develop an ion injection gun. <ref>{{cite web|url=http://www.talk-polywell.org/bb/viewtopic.php?p=11400&highlight=#11400 |title=Found this during google search on Polywell Fusion |publisher=Talk-polywell.org |date= |accessdate=2013-06-17}}</ref><ref>{{cite web
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| |url= http://www.talk-polywell.org/bb/viewtopic.php?p=11400&highlight=#11400
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| |title= Found this during google search on Polywell Fusion |accessdate=2008-11-07 |date=October 2008 |format= Discussion forum
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| |publisher= Talk-Polywell.org}}</ref> In December 2008, following many months of review by the expert review panel of the submission of the final WB-7 results, Dr Richard Nebel commented that "There's nothing in there [the research] that suggests this will not work," but that "That's a very different statement from saying that it will work."<ref>{{cite web |url= http://iecfusiontech.blogspot.com.br/2008/12/wb-6-results-confirmed-continuous.html |title= WB-6 Results Confirmed - Continuous Operation The Next Step |accessdate=2012-09-10 |date=October 2012|publisher= iecfusiontech.}}</ref>
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| In January 2009 the [[Naval Air Warfare Center]] pre-solicited another contract for "modification and testing of plasma wiffleball 7"<ref>{{cite web
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| |url=https://www.fbo.gov/index?s=opportunity&mode=form&tab=core&id=9cdc1fbbe6a740519220459e47f26249&_cview=0 |title=A—Plasma Wiffleball, Solicitation Number: N6893609R0024 |accessdate=2009-01-26
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| |date=January 2009 |publisher=Federal Business Opportunities
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| }}</ref> which appears to be funding to install the instrumentation developed in a prior contract, install a new design for the connector (joint) between coils, and operate the WB-7 with the modifications. The modified unit is now called WB-7.1. This pre-solicitation started as a $200k contract but the final award was for $300k.
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| In April 2009, the DoD published a plan to provide Polywell a further $2 million in funding as part of the [[American Recovery and Reinvestment Act of 2009]]. The citation in the legislation was labelled as ''Plasma Fusion (Polywell) - Demonstrate fusion plasma confinement system for shore and shipboard applications; Joint [[Office of the Secretary of Defense|OSD]]/USN project.''<ref>{{cite web |url=http://www.defenselink.mil/recovery/plans_reports/2009/march/Final_ARRA_Report_to_Congress-24_Mar_09ver2.pdf
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| |title=American Recovery and Reinvestment Act of 2009 - Department of Defense Expenditure Plans |accessdate=2009-05-05 |date=May 2009 |format=PDF Report to US Congress|publisher=Defencelink.mil}}</ref> The citation occurs 166 pages into the document, and suggests development of the device for 'Domestic Energy Supply / Distribution'.
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| == Navy contract for 12 million ==
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| In September 2009, the Recovery Act funded the Navy in the amount of $7.86M to construct and test a WB-8.<ref name="SOA-WB8">{{cite web |url=https://www.neco.navy.mil/upload/N68936/N6893609R0044RFP_09-R-0044.pdf |title=Statement of work for advanced gaseous electrostatic energy (AGEE) concept exploration |accessdate=2009-06-18
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| |date=June 2009 |format=PDF |publisher=United States Navy}}</ref> The Navy contract has an option for an additional $4.46M for "...based on the results of WB8 testing, and the availability of government funds the contractor shall develop a WB machine (WB8.1) which incorporates the knowledge and improvements gained in WB8. It is expected that higher ion drive capabilities will be added, and that a “PB11” reaction will be demonstrated".<ref name="SOA-WB8" /> This device increase the magnetic field strength eightfold over WB-6. The US Department of Defense announced this award as required by law. The announcement stated that the funding was provided for "research, analysis, development, and testing in support of the Plan Plasma Fusion (Polywell) Project. Efforts under this Recovery Act award will validate the basic physics of the Plasma Fusion (Polywell) concept, as well as provide the Navy with data for potential applications of polywell fusion." <ref>{{cite web |url=http://www.globalsecurity.org/military/library/news/2009/09/dod-contracts_4116.htm |title=U.S. Department of Defense - Office of the Assistant Secretary of Defense (Public Affairs) - Contracts |accessdate=2009-09-13 |date=September 2009 |publisher=United States Department of Defense }}</ref> The contract <ref name="SOA-WB8"/> had delivery dates for specific tasks these were:
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| * Completion of the WB-8 machine by April 30, 2010.
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| * Completion of device testing by April 30, 2011
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| * Completion of an optional second machine WB-8.1 by October 31, 2011.
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| * Completion of WB-8.1 machine testing by October 31, 2012.
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| === FY 2010 work ===
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| The team's progress was reported on the Recovery Act Tracking site in the form of quarterly reports.<ref name="Recovery" >{{cite web|url=http://www.recovery.gov/Transparency/RecipientReportedData/pages/RecipientProjectSummary508.aspx?AwardIdSur=46419&AwardType=Contracts |title=Project Summary - ENERGY/MATTER CONVERSION CORPORATION |publisher=Recovery.gov |date= |accessdate=2013-06-17}}</ref>
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| * The first quarterly report stated: "The main focus of this quarter was the design, procurement and construction of equipment for the new WB-8 Polywell device. Theoretical work was also initiated to build the computational tools required to analyze and understand the data from WB-8."<ref name="Recovery" />
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| * The second quarterly report stated: "on budget, on schedule for new lab test facility. Primary focus has been construction, procurement and relocation of personnel and chamber." (Slightly different format to award number so on a different page.)
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| * The fourth quarterly report stated: "WB8 is fully under construction, progress made on Theoretical modeling of the Polywell. 2 full-time physicists hired. (On the original page)." <ref name="Recovery" /> The location of work was also updated to San Diego. Confirmation of a lab move to San Diego was provided by an on-site visit.<ref>{{cite web|url=http://www.talk-polywell.org/bb/viewtopic.php?p=51065#51065 |title=Recovery.Gov Project Tracker Discussion at Talk-Polywell.org|publisher=Talk-Polywell.org |date= 2011-11-09|accessdate=2012-03-31}}</ref>
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| === FY 2011 work ===
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| A series of quarterly reports on the Recovery Act site followed the team's progress:<ref name="Recovery" />
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| * The first quarter report stated: "WB-8 device construction is completed. The first plasma was generated successfully on Nov. 1, 2010." <ref name="Recovery" /> The report listed Dr. Jaeyoung Park as the Company Officer.
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| * The second quarter report stated: "the WB-8 device operates as designed and it is generating positive results. EMC2 is planning to conduct comprehensive experiments on WB-8 in the next 9-12 months based on the current contract funding schedule." <ref name="Recovery" />
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| * The third quarter report stated: "As of 2Q/2011, the WB-8 device has demonstrated excellent plasma confinement properties. EMC2 is conducting high power pulsed experiments on WB-8 to test the Wiffle-Ball plasma scaling law on plasma energy and confinement." <ref name="Recovery" /> As of 3Q/2011, the WB-8 device had generated over 500 high power plasma shots. EMC2 is conducting tests on Wiffle-Ball plasma scaling law on plasma heating and confinement.<ref>{{cite web|url=http://www.recovery.gov/Transparency/RecipientReportedData/Pages/RecipientProjectSummary508.aspx?AwardIDSUR=46419&qtr=2011Q3 |title=Project Summary 2011 Q3 |publisher=Recovery.gov |date= |accessdate=2013-06-17}}</ref>
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| * The fourth quarter report of 2011 stated that the modification of the electron injectors increased the plasma heating. The higher plasma density in WB-8 prompted the need for higher heating power. They planned to operate WB-8 in high beta regime with the modified electron injectors during the first quarter of 2012.<ref>{{cite web|url=http://www.recovery.gov/Transparency/RecipientReportedData/pages/RecipientProjectSummary508.aspx?AwardIDSUR=46419&qtr=2011Q4 |title=Project Summary 2011 Q4|publisher=Recovery.gov |date= |accessdate=2012-03-31}}</ref>
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| In 2011, Dr. Jaeyoung Park became President of Energy Matter Conversion Corporation. <ref>{{cite web|url=http://www.talk-polywell.org/bb/viewtopic.php?t=1681&postdays=0&postorder=asc&start=345 |title=Recovery.Gov Project Tracker at Talk-Polywell.org |publisher=Talk-Polywell.org |date= 2011-04-29 |accessdate=2012-03-31}}</ref> In a May 2011 interview, Dr. Park commented that "This machine [WB8] should be able to generate 1,000 times more nuclear activity than WB-7, with about eight times more magnetic field.... We'll call that a good success." <ref>{{cite news |url=http://cosmiclog.msnbc.msn.com/_news/2011/05/10/6619613-fusion-goes-forward-from-the-fringe |title=Fusion goes forward from the fringe |work=msnbc.com |first=Alan |last=Boyle |accessdate=May 13, 2011}}</ref>
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| === FY 2012 work ===
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| As of August 15, 2012, the Navy had agreed to fund EMC2 with an additional $5.3 million over 2 years to work on the problem of pumping electrons into the whiffleball. They plan to integrate a pulsed power supply to support the electron guns (100+A, 10kV). WB-8 has been operating at 0.8 Tesla. The review of the work produced the recommendations to continue and expand the effort,<ref>https://www.fpds.gov/ezsearch/search.do?indexName=awardfull&templateName=1.4.3&s=FPDSNG.COM&q=energy%2Fmatter&sortBy=SIGNED_DATE&desc=Y</ref>stating: "The experimental results to date were consistent with the underlying theoretical framework of the polywell fusion concept and, in the opinion of the committee, merited continuation and expansion."<ref>[https://www.neco.navy.mil/synopsis_file/N6893609C0125%20_Redacted_JA.pdf Justification and Approval for Other than Full and Open Competition] p.2.</ref>
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| ==Other projects==
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| ===Prometheus Fusion Perfection===
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| Mark Suppes, a web developer, built his own polywell in a warehouse in Brooklyn, New York. He was the first amateur in the world to detect electron trapping using a [[Langmuir probe]] inside a polywell.<ref>Mark Suppes, Private Communication, May 30th 2013</ref> He presented at the 2012 LIFT conference and the 2012 WIRED conference.<ref>{{youtube|Jvkoklpubiw|WIRED video}}</ref> The project officially ended in July 2013, while the blog will remain online indefinitely.<ref>http://prometheusfusionperfection.com/2013/07/07/an-end-to-four-years-of-prometheus-fusion-perfection/</ref>
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| ===University of Sydney===
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| The [[University of Sydney]] in Australia have been conducting studies and experiments with polywell devices. To date, they have published four papers in Physics of Plasmas on this topic, one in 2010,<ref>{{cite doi|10.1063/1.3428744}}</ref> one in late 2011,<ref name="Low beta confinement in a Polywell modeled with conventional point cusp theories"/> and two in 2013.<ref name="Oct12013Paper">"Scaling law of electron confinement in a zero beta polywell device" Devid Gummershall, Matthew Carr, Scott Cornish, Physics of Plasma 20, 102701 (2013)</ref><ref name = "2013AussyWork">{{cite doi|10.1063/1.4804279}}</ref> They also published one PhD thesis<ref>[http://opac.library.usyd.edu.au/record=b4663898~S4, "Electrostatic potential measurements and point cusp theories applied to a low beta polywell fusion device" PhD Thesis, Matthew Carr, 2013, The University of Sydney]</ref> on the subject.
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| The May 2010 paper discussed experimental work, testing a small device for its ability to capture electrons. The paper posited that the machine had an ideal magnetic field strength which maximized its ability to catch electrons. The paper analyzed magnetic confinement in the polywell using analytical solutions as well as simulations. The work linked the magnetic confinement in the polywell to [[magnetic mirror]] theory.<ref name="F. Chen 1984 pp. 30"/> This research was presented at the 12th US-Japan Workshop on Inertial Electrostatic Confinement Fusion,<ref>{{cite web|url=http://www.plasma.ee.kansai-u.ac.jp/iec2010/Agenda.html |title=Agenda of 12th US-Japan Workshop on Inertial Electrostatic Confinement Fusion |date=2010-10-20 |accessdate=2013-06-17}}</ref> and summarized by John Santarius of the University of Wisconsin <ref>{{cite web|last=Santarius|first=John|title=Summary & Thoughts|url=http://fti.neep.wisc.edu/presentations/jfs_summary_iec2011.pdf|work=13th Workshop on Inertial-Electrostatic Confinement Fusion|publisher=University of Wisconsin|accessdate=31 March 2012}}</ref> The 2011 work uses [[Particle-in-cell]] simulations to model particle motion in polywells with a small electron population. Electrons behaved in a similar manner to particles in the [[biconic cusp]].<ref name="ReferenceA"/>
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| The first 2013 paper, measured a negative [[voltage]] inside a 4 inch aluminum polywell.<ref name="2013AussyWork"/> This was performed using pairs of biased [[Langmuir probe]]s. Several tests were undertaken that included: measuring an internal [[Charged particle beam|beam]] of electrons, comparing the machine with and without a [[magnetic field]], measuring the [[voltage]] at different locations and comparing voltage changes to the [[magnetic]] and [[electric]] field strength.<ref name="2013AussyWork"/>
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| === Iranian Nuclear Science and Technology Research Institute ===
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| In November 2012, Trend News Agency reported
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| that AEO Iran had allocated "$8 million"<ref>{{cite web|url=http://en.trend.az/regions/iran/2087514.html |title=NewsTrendsFromAzerbaijan |date=2012-11-13 |accessdate=2013-02-08}}</ref> to inertial electrostatic confinement research and about half had been spent. The funded group published a report in the ''Journal of Plasma Physics''. The report stated that particle-in-cell simulations of a polywell had been conducted. The study suggested that well depths and ion focus control can be achieved by variations of field strength. The report referenced older research with traditional fusors. The group had run a fusor in continuous mode at -140KV with 70mA of current, with D-D fuel, producing 2x10^7 neutrons per second.<ref>{{cite web|url=http://www.springerlink.com/content/146646h240747113/ |title=Journal of Fusion Energy, Online First™ |doi=10.1007/s10894-011-9474-4 |publisher=SpringerLink |date=2011-11-08 |accessdate=2012-03-31}}</ref>
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| === University of Wisconsin ===
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| Dr. Carl Sovinec and his graduate student have performed Vlasov-Poisson, [[particle-in-cell]] simulation work on the polywell. This was funded through the National Defense Science and Engineering Graduate Fellowship and was presented at the 2013 [[American Physical Society]] conference.<ref>{{cite web |url=http://absimage.aps.org/image/DPP13/MWS_DPP13-2013-000611.pdf |title=Vlasov-Poisson calculations of electron confinement times in Polywell(TM) devices using a steady-state particle-in-cell method |publisher=The DPP13 Meeting of The American Physical Society|date= |accessdate=2013-10-01}}</ref>
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| === Convergent Scientific Inc. ===
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| Convergent Scientific Inc, is a company which has an effort to build a small scale polywell fusing [[deuterium]].<ref>"Designing a Small-Scale D+D Reactor" Dr. Joel Rogers, The 14th US-Japan workshop on IECF, The University of Maryland, October 14th - 17th, 2012</ref><ref>{{cite web|url=http://convsci.com/login |title=Convergent Scientific Incorporated |publisher=Convsci.com |date= |accessdate=2013-06-17}}</ref> The company has a US patent on appeal <ref>US Patent office - Pair Database http://portal.uspto.gov/pair/PublicPair, US Patent Application, 12/141,644, accessed 1-2-2014</ref> and in the Fall of 2013, did a series of web-based investor pitches.<ref>Talk. "Introduction to Physics of IEC Devices." Web presentation, Preformed by Devlin Baker, October 22, 2013. http://sproutvideo.com/videos/1c9bd8bd171be4c994</ref><ref>Talk. "Numerical Simulations of IEC Plasmas." Web presentation, Preformed by Devlin Baker, November 5th, 2013. http://sproutvideo.com/videos/e89bd8bd1314edca60</ref> The presentations mention encountering plasma instabilities including the [[Diocotron instability|Diocotron]], [[Two-stream instability|two stream]] and [[Weibel instability|Weibel]] instabilities. The company wants to make and sell [[Nitrogen-13]] for [[Positron emission tomography | PET]] scans.<ref>Talk. "Commercial Applications of IEC Devices" Web presentation, Preformed by Devlin Baker, December 3rd, 2013. http://sproutvideo.com/videos/189bd8bd131be6c290</ref>
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| === Radiant Matter Research ===
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| Radiant Matter<ref>http://www.radiantmatter.com/content/farnsworth-fusor, Accessed: 12/25/2013</ref> is an organization in the Netherlands which has built a number of [[fusor]]s and has plans to build a polywell.
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| ==References in Literature==
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| The polywell has been referenced in two novels: "A Green Sun" by Charles Gray<ref>"A Green Sun (The Fusion Age)" By Charles Gray, August 7, 2011, Amazon Digital Services, Inc, http://www.amazon.com/Green-Sun-The-Fusion-Age-ebook/dp/B005GBPEAE</ref> and "To Fly from Folly" by William W Flint.<ref>"To Fly from Folly: Saving the Polywell", William W Flint Amazon Digital Services, Inc. November 2, 2013, http://www.amazon.com/dp/B00GF59ADC</ref>
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| == See also ==
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| {{columns-list|2|
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| * [[Fusor]]
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| * [[Magnetic mirror]]
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| * [[biconic cusp]]
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| * [[Inertial electrostatic confinement]]
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| * [[Bremsstrahlung]]
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| * [[Aneutronic fusion]], including the proton and Boron-11 fusion reaction
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| * [[Tokamak]]
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| * [[List of plasma (physics) articles]]
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| * [[Dense plasma focus]]
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| * [[Magnetized target fusion]]
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| * [[George H. Miley]]
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| * [[Nicholas Krall]]
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| * [[Robert W. Bussard]]
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| }}
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| == References ==
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| {{Reflist|2}}
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| == External links ==
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| * [http://www.polywellnuclearfusion.com/ Polywell Nuclear Fusion]
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| * {{youtube|FhL5VO2NStU|Should Google Go Nuclear?}} Video of Dr. Bussard's presentation to Google.
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| * [http://askmar.com/ConferenceNotes/Should%20Google%20Go%20Nuclear.pdf Should Google Go Nuclear?(transcript)] Illustrated transcript of Bussard's Google presentation.
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| * [http://isdc2.xisp.net/~kmiller/isdc_archive/fileDownload.php/?link=fileSelect&file_id=422 Presentation] at International Space Development Conference (ISDC). Dallas, May 2007.
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| * [http://www.strout.net/info/science/polywell/index.html Links] Compendium of informative links related to polywell fusion.
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| * [http://www.askmar.com/Fusion.html List] of technical papers and references.
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| * {{youtube|jmp1cg3-WDY|IEC Fusion for Dummies}} Graphical explanation of a polywell.
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| * [http://www.talk-polywell.org/bb/index.php Talk-Polywell.org] BBS for discussing polywell.
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| * [http://iec.neep.wisc.edu/overview.php University of Wisconsin–Madison] Introduction to [[inertial electrostatic confinement|IEC]] including the polywell.
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| * [http://www.santafenewmexican.com/SantaFeNorthernNM/Robert_Bussard__1928_2007_Physicist_known_for_pursuits_into_fus Obituary for Dr. Bussard].
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| * [http://cosmiclog.msnbc.msn.com/archive/2008/06/12/1136887.aspx Latest Fusion developments (WB-7 - June 2008) based on the work of Dr. Robert Bussard]
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| * [http://prometheusfusionperfection.com/ Prometheus Fusion] - A blog describing amateur experiments aimed at creating a polywell.
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| * {{youtube user|happyjack27|Simulation videos of a polywell reactor}}
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| * [http://thepolywellblog.blogspot.com/ The Polywell Blog] - An amateur blog discussing the polywell.
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| * [http://www.youtube.com/watch?v=Jvkoklpubiw/ Wired 2012 Presentation] - Mark Suppes talk at Wired 2012 on the polywell.
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| * [http://www.youtube.com/watch?v=IFp0WFCK714 Polywell 101] A 10 minute film explaining the polywell.
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| {{Fusion methods}}
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| {{Nuclear fusion reactors}}
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| [[Category:Fusion power]]
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| [[Category:Plasma physics]]
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