In:
Physics of Plasmas, AIP Publishing, Vol. 22, No. 10 ( 2015-10-01)
Abstract:
The nonlinear properties of q ≳ 1 non-resonant fishbone (NRF) instabilities excited by energetic ions are analyzed theoretically for weakly reversed shear in this work. Nonlinear radial displacement of the NRF mode ξ0 is derived by the method of matched asymptotic expansions. It is found that ξ0 depends on the energetic ion beta in a power law of ∼βhα with α=1/3, α=1/7, and α≪1, corresponding to a finite qs″, qs″=0, and an extremely flattened q-profile, respectively. The scaling dependence of ξ0 on the linear growth rate ∼γ1/4 is also different from that of ∼γ in a conventional positive shear configuration. The scaling suggests that ξ0 weakly depends on βh and γ when the q-profile is flattened. Nonlinear saturation amplitude of the mode for an ITER-like plasma is also estimated by numerical analysis.
Type of Medium:
Online Resource
ISSN:
1070-664X
,
1089-7674
Language:
English
Publisher:
AIP Publishing
Publication Date:
2015
detail.hit.zdb_id:
1472746-8
Permalink