Parametric instabilities during the experiment on ion Bernstein wave heating of tokamak plasma
Parametric instabilities in the scenario of the ion Bernstein wave (IBW) plasma heating experiment were investigated. Theoretical analysis shows that the RF power threshold of the instabilities is very low when the plasma density near the antenna meets certain conditions. The threshold becomes very high and is determined by the convective losses due to the plasma inhomogeneity when the plasma density near the antenna is sufficiently high. According to the theory, the parametric instability activity should increase if the plasma is moved away from the antenna, creating a low density electron plasma wave gap region. This hypothesis is in agreement with the behaviour of the parametric instability obtained during the IBW experiment on PBX-M. This result shows that the parametric instability activity observed can be explained in terms of the plasma inhomogeneity convective model. Also, by controlling the plasma position relative to the antenna, parametric instability activity can be controlled at a low level.
Bibliographic Reference: Paper presented: 2nd International Workshop Strong Microwaves in Plasmas, Novgorod (SU), August 15-22, 1993
Availability: Available from (1) as Paper EN 37938 ORA
Record Number: 199311493 / Last updated on: 1994-11-28
Original language: en
Available languages: en