A Novel Means for Nuclear Fusion (original) (raw)
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1991 US-Japan workshop on Nuclear Fusion in Dense Plasmas. Proceedings
1991
We have measured the electrical resistivity of a dense polyurethane plasma that is produced in a capillary discharge. These discharges are produced by passing a large current, 250 kA, through a 20 micron hole in a block of polyurethane. The current ,causes material to be ablated off the wall that is then ohmically heated, producing a plasma with density of 5x1021 cm-3 and a temperature of 25-30 eV. The resistivity is determined by measuring the voltage across the plasma, the current through it, and the size of the discharge channel. To compare our results to the many theories of dense plasmas, we must also determine the density and temperature. The temperature is measured using an x-ray pinhole framing camera and the density is determined from calculations using a sophisticated 1-D MHD model. We compare our results to several theories and find that the resistivity we measure is higher than predicted for each case. We also find that the MHD model cannot predict the size of the discharge channe_ as accurately as we expect. This leads us to conclude that the pressure in the discharge is not given by the ideal gas law but is slightly less, as some have predicted. Ongoing experiments on dense aluminum and copper plasmas will also be discussed.
The Plasma Compression Fusion Device-Enabling Nuclear Fusion Ignition
The plasma compression fusion device (PCFD) generates the energy gain by plasma compression-induced nuclear fusion. This concept has the capability of maximizing the product of plasma pressure and energy confinement time to maximize the energy gain, and thus give rise to fusion ignition conditions. The preferred embodiment of this original concept uses a hollow cross-duct configuration of circular cross section in which the concentrated magnetic energy flux from two pairs of opposing curved-headed counter-spinning conical structures (possibly made from an alloy of tungsten with high capacitance) whose outer surfaces are electrically charged compresses a gaseous mixture of fusion fuel into a plasma, heated to extreme temperatures and pressures. The generated high-intensity electromagnetic (EM) radiation heats the plasma and the produced magnetic fields confine it in between the counter-spinning conical structures, named the dynamic fusors (four of them-smoothly curved apex sections opposing each other in pairs). The dynamic fusors can be assemblies of electrified grids and toroidal magnetic coils, arranged within a conical structure whose outer surface is electrically charged. The cross-duct inner surface surrounding the plasma core region is also electrically charged and vibrated in an accelerated mode to minimize the flux of plasma particles (including neutrals) from impacting the PCFD surfaces and initiating a plasma quench. The fusion fuel (preferably deuterium gas) is introduced into the plasma core through the counterspinning conical structures, namely, injected through orifices in the dynamic fusor heads. There is envisioned another even more compact version of this concept, which uses accelerated vibration in a linear-duct configuration (using two counterspinning dynamic fusors only) and would best be suited for fusion power generation on aircraft, or main battle tanks. The concept uses controlled motion of electrically charged matter through accelerated vibration and/or accelerated spin subjected to smooth, yet rapid acceleration transients, to generate extremely high-energy/high-intensity EM radiation (fields of high-energy photons) which not only confines the plasma but also greatly compresses it so as to produce a high power density plasma burn, leading to ignition. The PCFD concept can produce power in the gigawatt to terawatt range (and higher) with input power in the kilowatt to megawatt range and can possibly lead to ignition (selfsustained) plasma burn. Several important practical engineering and operational issues with operating a device such as the PCFD are discussed.
Increased nuclear fusion yields of inertially confined DT plasma due to reheat
Zeitschrift Fur Naturforschung a, 1978
The efficiency of energy release has been calculated here for fusion reactions in inertially confined plasmas of high density. It is found that inclusion of reheat due to absorption of the energetic alphas released by the reactions in the plasma itself predicts higher gains G due to ignition. Including losses by bremsstrahlung and fuel depletion we find G 71 for 1 kJ laser energy input with a compression of only 1000 times solid state density.
Progress of Theoretical Physics Supplement, 2004
We investigate the possibility of gaining energy from nuclear fusion reactions using different mixtures of D, T and 6 Li. First, a plasma in equilibrium is studied at different densities and temperatures. In a second, highly non equilibrium case, the plasma is at high densities and excitation energies. While the first case could lead to an energy gain especially when coupled to an accelerator, in the second case the energy given to the system might be larger than the output energy even for a D+T plasma. This is due to the small number of particles which can be treated numerically. Furthermore, there is a possible double counting between the elementary fusion cross section and the exact Coulomb potential used in the calculations.
Fusion energy in degenerate plasmas
Physics Letters A, 2005
In inertial confinement fusion (ICF), a high density, low temperature plasma can be obtained during the compression phase, so minimizing the energy needed for compression. If the final temperature reached is low enough, the electrons of the plasma can be degenerate. In this case, bremsstrahlung emission is strongly suppressed and ignition temperature becomes lower than in classical plasmas, which offers a new design window for ICF. Fusion ignition can then be triggered by an additional energy beam. The main difficulties to produce degenerate plasmas are the compression energy and the compression performance needed for it. Besides that, the low specific heat of degenerate electrons (as compared to classical values) is also a problem because of the rapid heating of the plasma. The main contribution of the Letter is to show that the plasma degeneracy lowers the ignition temperature for DT plasmas, but it does not increase the target energy gain. Some numerical results are given on that. In the case of proton-boron 11 plasmas, the densities have to be extremely high in order to reduce the ignition temperature, but even so the energy gains remain rather low.
Thermonuclear Ignition By Means of Compact Devices*
2009
This issue of the International Journal of Fusion Energy contains the first article to appear here on the engineering frontiers of fusion research. Coauthored by Bruno Coppi, one of the foremost plasma physicists in the world today, whose work is unique for its geographical scope as well as for the way in which it encompasses both the engineering and theoretical aspects of fusion, this paper is an exciting introduction to the forefront of the practical problems in fusion research and the development of a commercial power reactor. The second article in this issue is a research review, covering the Sept. 1979 workshop in LaJolla, California, on structured states in turbulent fluids, which was attended by two directors of the Fusion Energy Foundation. This is the last issue of the UFE to appear in the present quarterly format; beginning with the next issue, the redesigned journal will appear semiannually as a much more extensive publication, with room for several longer articles. The editors look forward to this greater freedom to publish significant works and translations of historical breakthroughs in full. An annual review of engineering and theoretical progress in fusion physics will now become a regular UFE feature. Each issue of the new UFE will thus replace two issues of the shorter journal for subscription purposes. Authors wishing to submit manuscripts for publication in UFE should send two (double-spaced) copies of their work with stats oj all figures to the Managing Editor.
Fusion Heating in a Deuterium-Tritium Tokamak Plasma
Physical Review Letters, 1996
Evidence for fusion heating in the core of a deuterium-tritium (D-T) tokamak plasma is reported for the first time. Electron temperature profile data were analyzed for differences between D-T, D, and T plasmas in the Tokamak Fusion Test Reactor. Data from D and D-T plasmas with similar plasma parameters were averaged to minimize isotopic effects. The electron temperature in D-T plasmas was systematically higher than in D or T plasmas. The temperature difference between D-T and D plasmas with similar confinement times is consistent with alpha-particle heating of electrons.