Phase contrast imaging measurements of reversed shear Alfven eigenmodes during sawteeth in Alcator C-Mod
Author(s)Edlund, Eric Matthias; Porkolab, Miklos; Kramer, G. J.; Lin, Liang; Lin, Yijun; Wukitch, Stephen James; ... Show more Show less
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Reversed shear Alfvén eigenmodes (RSAEs) have been observed with the phase contrast imaging diagnostic and Mirnov coils during the sawtooth cycle in Alcator C-mod [M. Greenwald et al., Nucl. Fusion 45, S109 (2005)] plasmas with minority ion-cyclotron resonance heating. Both down-chirping RSAEs and up-chirping RSAEs have been observed during the sawtooth cycle. Experimental measurements of the spatial structure of the RSAEs are compared to theoretical models based on the code NOVA [C. Z. Cheng and M. S. Chance, J. Comput. Phys. 71, 124 (1987)] and used to derive constraints on the q profile. It is shown that the observed RSAEs can be understood by assuming a reversed shear q profile (up chirping) or a q profile with a local maximum (down chirping) with q[approximate]1.
DepartmentMassachusetts Institute of Technology. Department of Physics; Massachusetts Institute of Technology. Plasma Science and Fusion Center
Physics of Plasmas
American Institute of Physics
Edlund, E. M. et al. “Phase contrast imaging measurements of reversed shear Alfv[e-acute]n eigenmodes during sawteeth in Alcator C-Mod.” Physics of Plasmas 16.5 (2009): 056106-8. ©2009 American Institute of Physics.
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