Modified magnetic confinement configurations based on understanding helicity dissipation and pressure driven modes in the spheromak [electronic resource].
- Los Alamos, N.M. : Los Alamos National Laboratory, 1988. and Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
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- Pages: 2 : digital, PDF file
- Additional Creators:
- Los Alamos National Laboratory and United States. Department of Energy. Office of Scientific and Technical Information
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- Free-to-read Unrestricted online access
- Recent results from the spheromak work at Los Alamos include: In decaying spheromaks in the mesh flux conserver, the rate of current decay dI/dt depends only on the density n/sub e/ (not on I or T/sub e/ as might be expected classically). The particular dependence of dI/dt on n/sub e/ suggests that most of the helicity is dissipated in the field error regions at the edge where electron-neutral hydrogen collisions dominate the electrical resistance. A new solid-wall, titanium-gettered flux conserver has been commissioned, resulting in less field errors than with previous mesh flux conserver. A factor of four decrease in dI/dt has been observed. In this new flux conserver, clear evidence of a pressure-driven instability has been obtained. To our knowledge, this is the first time a pressure driven interchange mode has been directly observed in a toroidal geometry. Peak ..beta.. values observed before the onset of the mode are of the same order as those predicted at the corresponding Mercier limits (..beta../sub c/ approx. 1%). As a result, flux conserver shapes with higher ..beta../sub c/ are now being considered by us. The ..beta../sub c/ calculations have been made using Taylor-like (minimum energy) magnetic profiles. By changing the flux conserver shape, the q profile of the minimum-energy state can be varied continuously from RFP-like to tokamak-like. The highest ..beta../sub c/ (approx.10%) are found at these two extremes of the range of magnetic configurations. 3 refs.
- Published through SciTech Connect., 01/01/1988., "la-ur-88-1104", " conf-881015-1", "DE88009149", 12. international conference on plasma physics and controlled nuclear fusion research, Nice, France, 12 Oct 1988., and Barnes, C.W.; Henins, I.; Jarboe, T.R.; Fernandez, J.C.; Wysocki, F.J.; Marklin, G.J.
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