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(EXP2/03) The Combined Effect of EPM and TAE Modes on Energetic Confinement and Sawtooth Stabilization

S. Bernabei¹⁾, R. Budny¹⁾, E. Fredrickson¹⁾, N. N. Gorelenkov¹⁾, R. W. Harvey³⁾, J. C. Hosea¹⁾, C. C. Petty²⁾, C. K. Phillips¹⁾, R. I. Pinsker²⁾, P. Smirnov⁴⁾, R. White¹⁾, J. R. Wilson^1)
 
1) Princeton Plasma Physics Laboratory, Princeton N.J. 08540
²⁾ General Atomics, San Diego, California 92186
³⁾ CompX, P.O. Box 2672, Del Mar, California 92014
⁴⁾ Moscow State University, Moscow, Russia.

Abstract.  It is shown in this paper for the first time, that the chirping Alfvén instabilities observed mostly during ICRF heating have been positively identified as Energetic Particle Modes. This has been possible because of the detailed measurement of the q-profile with the MSE diagnostic in DIII-D. The EPMs are shown to be the leading cause of the monster sawtooth crash. It is also shown that TAEs are excited either directly or indirectly by the EPMs and they cause fast ion losses. A scenario for the stabilization and the crash of the monster sawtooth and for the degradation of the ICRF heating efficiency at high power is presented.

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