Spectroscopic determination of kinetic parameters for frequency sweeping Alfven eigenmodes
- Japan Atomic Energy Agency, Higashi-Ueno 6-9-3, Taitou, Tokyo 110-0015 (Japan)
- Japan Atomic Energy Agency, Mukouyama 801-1, Naka, Ibaraki 311-0193 (Japan)
- IRFM, Commissariat a l'Energie Atomique, F-13108 Saint Paul Lez Durance (France)
A method for analyzing fundamental kinetic plasma parameters, such as linear drive and external damping rate, based on experimental observations of chirping Alfven eigenmodes, is presented. The method, which relies on new semiempirical laws for nonlinear chirping characteristics, consists of fitting procedures between the so-called Berk-Breizman model and the experiment in a quasiperiodic chirping regime. This approach is applied to the toroidicity induced Alfven eigenmode (TAE) on JT-60 Upgrade (JT-60U) [N. Oyama et al., Nucl. Fusion 49, 104007 (2009)], which yields an estimation of the kinetic parameters and suggests the existence of TAEs far from marginal stability. Two collision models are considered, and it is shown that dynamical friction and velocity-space diffusion are essential to reproduce nonlinear features observed in experiments. The results are validated by recovering measured growth and decay of perturbation amplitude and by estimating collision frequencies from experimental equilibrium data.
- OSTI ID:
- 21532079
- Journal Information:
- Physics of Plasmas, Vol. 17, Issue 12; Other Information: DOI: 10.1063/1.3500224; (c) 2010 American Institute of Physics; ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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