Study of parametric instabilities during the ion Bernstein wave heating experiment on PBX-M
Parametric instabilities during the ion Bernstein wave (IBW) experiment of plasma heating on PBX-M are investigated both theoretically and experimentally. According to the theory, the parametric instability activity should increase as the plasma is moved away from the antenna, creating a low density electron plasma wave gap region. To test this hypothesis on PBX-M, the plasma position was deliberately varied while monitoring this activity. Under normal IBW operating conditions, very little parametric instability activity was observed up to 50 dB below the pump wave. However, when the plasma edge was moved away from the antenna by about 2 cm, the parametric instability activity increased greatly, exceeding 20 dB of the pump wave. This result shows that the observed parametric instability activity can be explained in terms of the plasma inhomogeneity convective model. It was also demonstrated that, by controlling the plasma position with respect to the antenna, parametric instability activity can be controlled at a low level.
Bibliographic Reference: Report: RT/ERG/FUS/93/07 EN (1993)
Availability: Available from Servizio Studi e Documentazione, ENEA, Centro Ricerche Energia Frascati, C.P. 65-00044 Frascati, Roma (IT)
Record Number: 199410051 / Last updated on: 1994-11-28
Original language: en
Available languages: en