SAWTEETH AND DISRUPTIONS IN JET
The behaviour of magnetohydrodynamic phenomena associated with sawteeth and major disruptions has been studied for a wide range of discharge conditions with ohmic, neutral beam and ion cyclotron heating. The sawtooth collapse has been investigated in detail and found to be inconsistent with models based on resistive reconnection. Disruptions set limits to JET operation at low q and high density, and the detailed evolution of disruptions at these limits has been studied. A hard operational limit is found at q-psi=2.0 +-0.1. The highest value of the Murakami parameter achieved in ohmic plasmas is nR/B-T = 7.2 10**19m**-2T**-1, but neutral beam heating leads to a substantial increase (about 50%) in the density limit. Finally, during high power neutral beam heating combined with ion cyclotron heating "monster" sawteeth are observed in which mhd activity of modes with low m and n becomes quiescent for periods about 1s.
Bibliographic Reference: 11TH INTERNATIONAL CONFERENCE ON PLASMA PHYSICS AND CONTROLLED NUCLEAR FUSION RESEARCH, KYOTO (JAPAN), NOV. 13-20, 1986 WRITE TO THE PUBLICATIONS OFFICER, JET JOINT UNDERTAKING, ABINGDON, OXON OX14 3EA (UK), MENTIONING REPORT JET-P(86)44, 1986
Record Number: 1989125079700 / Last updated on: 1987-12-01
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