Fast particle finite orbit width and Larmor radius effects on low-n toroidicity induced Alfvén eigenmode excitation

N. N. Gorelenkov, Chio-Zong Cheng, G. Y. Fu

Research output: Contribution to journalArticlepeer-review

82 Citations (Scopus)

Abstract

The effects of finite drift orbit width (FOW) and Larmor radius (FLR) of fast particles on the stability of low-n toroidicity-induced Alfvén eigenmodes (TAE) are studied. The formulation is based on the solution of the low frequency gyrokinetic equation (ω<ωc, where ωc is particle cyclotron frequency). A quadratic form has been derived in terms of invariant variables; energy ε, magnetic moment μ, and toroidal angular momentum Pφ. The growth rate of the TAE is computed perturbatively using numerical averaging over the fast particle drift orbit. This new computational capability improves the NOVA-K code [G. Y. Fu, C. Z. Cheng, and K. L. Wong, Phys. Fluids B 5, 4040 (1994)] which included FOW effects in the growth rate calculation based on small radial orbit width approximation. The new NOVA-K version has been benchmarked for different regimes of particle TAE excitation. It is shown that both FOW and FLR effects are typically stabilizing; the TAE growth rate can be reduced by as much as a factor of 2 for tokamak fusion test reactor supershots [D. J. Grove and D. M. Meade, Nucl. Fusion 25, 1167 (1985)]. However, FOW may be destabilizing for the global modes, which are localized at the plasma edge

Original languageEnglish
Pages (from-to)2802-2807
Number of pages6
JournalPhysics of Plasmas
Volume6
Issue number7
DOIs
Publication statusPublished - 1999 Jan 1

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics

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