DISCONTINUOUS HEATING BEHAVIOUR OBSERVED IN THE TCA TOKAMAK AND ITS INTERPRETATION IN TERMS OF THE ALFVEN WAVE SPECTRUM
During a heating pulse in conditions which excite a resonance surface in the outer half of the plasma, a sharp discontinuity was observed in many of the plasma parameters. This feature occurs when a new mode appears in the spectrum and hence presumably the energy deposition profile is changed. This mode was not predicted by any of the theoretical calculations the Alfven wave spectrum. A tentative characterisation as a poloidally symmetric mode excited via toroidal coupling was made, and we have continued attempts to identify it and hence understand the reasons for its effect. These attempts, as described in this paper, have followed two directions. Firstly detailed experiments and analyses have been performed to determine which antenna structures can excite the mode and to quantify the effects of heating both with and without the mode in the plasma. Secondly we have used a modified version of the ERATO stability code to give a two dimensional model of the excitation process, we have been able to confirm our earlier indentification of the new mode, and to show that it is due to toroidal coupling of different poloidal modes in the plasma.
Bibliographic Reference: 4TH INTERNATIONAL SYMPOSIUM ON HEATING IN TOROIDAL PLASMAS, ROMA (ITALY), MARCH 21-28, 1984 WRITE TO CEC LUXEMBOURG, DG XIII/A2, POB 1907 MENTIONING PAPER E 31459 ORA
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Record Number: 1989122086300 / Last updated on: 1987-01-01
Available languages: en