Dynamical plasma response to additional heating
This paper presents results of the dynamical response on the electron temperature, deduced from the soft X-ray emissivity profile, to additional Alfven Wave Heating Power. This study used quasi-steady state sinusoidal modulation of the delivered r.f. power, but data are also included on the step-function response at the end of the r.f. pulse, and the impulse response to short periodic r.f. pulses. These different approaches show similar behaviour of the radial profile of the response phase, which is dominated by a central flat region within the q = 1 surface with, at the higher frequencies used, a minimum phase of close to 180degrees. Moving further outside the q = 1 radius the phase increases extremely sharply. This basic character of the phase profile is not altered by varying the calculated power deposition profile but is still defined by the q = 1 radius, demonstrated by a plasma current scan at constant toroidal field. In addition to the soft X-ray flux baseline modulation, the sawtooth period is modulated, but out of phase with r.f. power. These effects have been studied as a function of modulation frequency, plasma current, r.f. power and Alfven wave mode.
Bibliographic Reference: Article: Plasma Physics and Controlled Fusion Vol.30 (1988) No. 6, pp. 743-762
Record Number: 198910338 / Last updated on: 1994-12-01
Original language: en
Available languages: en