Experimental Study of Reversed Shear Alfven Eigenmodes During The Current Ramp In The Alcator C-Mod Tokamak

Edlund, E. M. ; Porkolab, M. ; Kramer, G. J. ; Lin, L. ; Lin, Y. ; Tsuji, N. ; Wukitch, S. J.

关键词: ALCATOR DEVICE;    ALFVEN WAVES;    PLASMA;    COMPRESSIBILITY;    IONS;    ELECTRONS;    KINETICS;    MAGNETIC FIELDS;    REVERSED SHEAR;   

DOI  :  10.2172/988883
RP-ID  :  PPPL-4544
PID  :  OSTI ID: 988883
Others  :  TRN: US1007424

学科分类：原子、分子光学和等离子物理

美国|英语

来源: SciTech Connect

【 摘 要 】

Experiments conducted in the Alcator C-Mod tokamak at MIT have explored the physics of reversed shear Alfven eigenmodes (RSAEs) during the current ramp. The frequency evolution of the RSAEs throughout the current ramp provides a constraint on the evolution of qmin, a result which is important in transport modeling and for comparison with other diagnostics which directly measure the magnetic field line structure. Additionally, a scaling of the RSAE minimum frequency with the sound speed is used to derive a measure of the adiabatic index, a measure of the plasma compressibility. This scaling bounds the adiabatic index at 1.40 ?? 0:15 used in MHD models and supports the kinetic calculation of separate electron and ion compressibilities with an ion adiabatic index close to 7~4.