Numerical Study of Field-reversed Configurations: The Formation and Ion Spin-up

Belova, E. V. ; Davidson, R. C. ; Ji, H. ; Yamada, M. ; Cothran, C. D. ; Brown, M. R. ; Schaffer, M. J.

Princeton University. Plasma Physics Laboratory.

关键词: Numerical Simulation;    Saturation;    Decay;    75 Condensed Matter Physics, Superconductivity And Superfluidity;    70 Plasma Physics And Fusion Technology;   

DOI  :  10.2172/840784
RP-ID  :  PPPL-4075
RP-ID  :  AC02-76CH03073
RP-ID  :  840784

美国|英语

来源: UNT Digital Library

【 摘 要 】

Results of three-dimensional numerical simulations of field-reversed configurations (FRCs) are presented. Emphasis of this work is on the nonlinear evolution of magnetohydrodynamic (MHD) instabilities in kinetic FRCs, and the new FRC formation method by counter-helicity spheromak merging. Kinetic simulations show nonlinear saturation of the n = 1 tilt mode, where n is the toroidal mode number. The n = 2 and n = 3 rotational modes are observed to grow during the nonlinear phase of the tilt instability due to the ion spin-up in the toroidal direction. The ion toroidal spin-up is shown to be related to the resistive decay of the internal flux, and the resulting loss of particle confinement. Three-dimensional MHD simulations of counter-helicity spheromak merging and FRC formation show good qualitative agreement with results from the SSX-FRC experiment. The simulations show formation of an FRC in about 20-30 Alfven times for typical experimental parameters. The growth rate of the n = 1 tilt mode is shown to be significantly reduced compared to the MHD growth rate due to the large plasma viscosity and field-line-tying effects.