Combined Ideal and Kinetic Effects on Reversed Shear Alfven Eigenmodes
Authors: N.N. Gorelenkov, G.J. Kramer, and R. Nazikian
Abstract: A theory of Reversed Shear Alfven Eigenmodes (RSAEs) is developed for reversed magnetic
field shear plasmas when the safety factor minimum, qmin, is at or above a rational value. The
modes we study are known sometimes as either the bottom of the frequency sweep or the down
sweeping RSAEs. We show that the ideal MHD theory is not compatible with the eigenmode
solution in the reversed shear plasma with qmin above integer values. Corrected by special analytic
FLR condition MHD dispersion of these modes nevertheless can be developed. Large radial scale
part of the analytic RSAE solution can be obtained from ideal MHD and expressed in terms of the
Legendre functions. The kinetic equation with FLR effects for the eigenmode is solved numerically
and agrees with the analytic solutions. Properties of RSAEs and their potential implications for
plasma diagnostics are discussed.
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Submitted to: Physics of Plasmas (May 2011)
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Download PPPL-4626 (pdf 566 KB 26pp)
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