m=2 mode activity during lower hybrid current drive in ASDEX
The behaviour of the (2, 1) tearing mode in Lower Hybrid Current Drive (LHCD) discharges in ASDEX is examined. Due to the change in the current profile j(r), this mode can be destabilised during LHCD. This often leads to mode locking and a disruption, thereby limiting the amount of LH power that can be transferred to the plasma during current drive. A statistical analysis for two different current drive spectra shows that this power limit is dependent on both plasma current and line-averaged electron density. The possibilities of disruption control are discussed. It is shown that tailoring of the LHCD spectra might avoid the occurrence of the (2, 1) mode.
Bibliographic Reference: Article: Plasma Physics and Controlled Fusion, Vol. 33 (1991) No. 12, pp. 1423-1434
Record Number: 199111516 / Last updated on: 1994-12-02
Original language: en
Available languages: en