User:Graham.Fountain/Polywell lead section
The polywell is a type of nuclear fusion reactor. It is one of a number of types of reactor, based on inertial electrostatic confinement, which use an electric field to accelerate charged ions and heat them to conditions suitable for nuclear fusion: as the positively charged ions, which are injected into the reactor, are accelerated by the electric field, their kinetic energy rises, and if they collide at the center they can fuse together to form new types of atomic nuclei and release energy.[1] This electric field is generated in a polywell by trapping negatively charged electrons in a null at the center of a magnetic field. These trapped electrons then form a virtual cathode and create a negative voltage drop, or potential well. The magnetic field that traps the electons is generated by a set of electromagnets arranged in the shape of a polyhedron; hence, the name "polywell" from the contraction of "polyhedral" and "potential well". This is closely related to the magnetic mirror, the biconic cusp and the high beta fusion reactor.
The polywell was developed by the late Dr Robert Bussard and the company he founded in 1985, Energy/Matter Conversion Corporation, Inc. (EMC2), with funding from the Defense Threat Reduction Agency, DARPA, and the U.S. Navy. However, the first known proposal to combine this magnetic configuration with an electrostatic potential well in order to improve electron confinement was made by Oleg Lavrentiev in 1975.[2] Bussard and EMC2 developed the polywell as an improvement on another inertial electrostatic confinement fusion reactor, the fusor. Fusors suffer from high conduction losses, because of the way the electic field is generated by a charged wire cage, which most of the ions accelerated towards the center fall into. Hence, no fusor has ever come close to break-even energy output. Whereas the polywell, which does not have this cage, is claimed to be capable of net power production,[3][4] potentially from aneutronic fusion (without producing neutrons); in which case, it should require relatively low levels of biological shielding.[5]
- ^ "Inertial Electrostatic confinement (IEC) fusion fundamentals and applications", Springer, December 2013, by George Miley and S Krupakar Murali
- ^ Lavrent'ev, O. A. (4–7 March 1974). Electrostatic and Electromagnetic High-Temperature Plasma Traps. Conference on Electrostatic and Electromagnetic Confinement of Plasmas and the Phenomenology of Relativistic Electron Beams. Annals of the New York Academy of Sciences. Vol. 251. New York City: New York Academy of Sciences (published 8 May 1975). pp. 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 by Lavrent'ev.
{{cite conference}}: External link in|quote=|publicationdate=ignored (|publication-date=suggested) (help) - ^ "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
- ^ "A general critique of internal-electrostatic confinement fusion systems" Plasma Physics, June 1995, Todd Rider, MIT
- ^ El Guebaly, Laial, A., Shielding design options and impact on reactor size and cost for the advanced fuel reactor Aploo, Proceedings- Symposium on Fusion Engineering, v.1, 1989, pp.388–391. This design refers to D–He3, which actually produces more neutrons than p–11B fuel.