TY - JOUR

T1 - Kinetic extensions of magnetohydrodynamics for axisymmetric toroidal plasmas

AU - Cheng, C. Z.

N1 - Funding Information:
supported by US DOE Contract No. DE-ACO2-76-CHO3073.

PY - 1992/2

Y1 - 1992/2

N2 - A nonvariational kinetic-MHD stability code (NOVA-K) has been developed to integrate non-Hermitian integro-differential eigenmode equations due to energetic particles in a general flux coordinate (ψ, θ, ζ) system with an arbitrary Jacobian. The NOVA-K code employs the Galerkin method involving Fourier expansions in the generalized poloidal angle θ and generalized toroidal angle ζ directions, and cubic-B spline finite elements in the radial ψ direction. Extensive comparisons with the existing variational ideal MHD codes show that the NOVA-K code coverages faster and gives more accurate results. We have employed the NOVA-K code to study the effects of energetic particles on MHD type modes: (1) the stabilization of ideal MHD internal kink modes and the excitation of "fishbone" internal kink modes; (2) the α-particle destabilization of toroidicity-induced Alfvén eigenmodes (TAE) via transit and/or trapped particle resonances. Analytical theories are also presented to help explain the NOVA-K results. For energetic trapped particles generated by neutral-beam injection (NBI) and ion cyclotron resonant heating (ICRH) a stability window for the n = 1 internal kink mode in the hot particle beta space exists. On the other hand, the trapped α-particles can resonantly destabilize the n = 1 resonant fishbone mode even for total plasma β value smaller than the β threshold value for the n = 1 ideal internal kink mode. Finally, we show that the TAE modes can be destabilizedby α-particles via inverse Landau damping associated with the spatial gradient of the α-particle pressure with very low α-particle β threshold in the order of 10-4 for major tokamak DT experiments.

AB - A nonvariational kinetic-MHD stability code (NOVA-K) has been developed to integrate non-Hermitian integro-differential eigenmode equations due to energetic particles in a general flux coordinate (ψ, θ, ζ) system with an arbitrary Jacobian. The NOVA-K code employs the Galerkin method involving Fourier expansions in the generalized poloidal angle θ and generalized toroidal angle ζ directions, and cubic-B spline finite elements in the radial ψ direction. Extensive comparisons with the existing variational ideal MHD codes show that the NOVA-K code coverages faster and gives more accurate results. We have employed the NOVA-K code to study the effects of energetic particles on MHD type modes: (1) the stabilization of ideal MHD internal kink modes and the excitation of "fishbone" internal kink modes; (2) the α-particle destabilization of toroidicity-induced Alfvén eigenmodes (TAE) via transit and/or trapped particle resonances. Analytical theories are also presented to help explain the NOVA-K results. For energetic trapped particles generated by neutral-beam injection (NBI) and ion cyclotron resonant heating (ICRH) a stability window for the n = 1 internal kink mode in the hot particle beta space exists. On the other hand, the trapped α-particles can resonantly destabilize the n = 1 resonant fishbone mode even for total plasma β value smaller than the β threshold value for the n = 1 ideal internal kink mode. Finally, we show that the TAE modes can be destabilizedby α-particles via inverse Landau damping associated with the spatial gradient of the α-particle pressure with very low α-particle β threshold in the order of 10-4 for major tokamak DT experiments.

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U2 - 10.1016/0370-1573(92)90166-W

DO - 10.1016/0370-1573(92)90166-W

M3 - Review article

AN - SCOPUS:0001936446

VL - 211

SP - 1

EP - 51

JO - Physics Reports

JF - Physics Reports

SN - 0370-1573

IS - 1

ER -