MHD stability analysis on helical system with bootstrap current including electric field effects
The effect of the electrostatic potential Phi on the bootstrap current has been calculated and its impact on the global ideal MHD stability of a LHD configuration has been investigated. The bootstrap current can destabilise a m/n=2/3 external kink when it causes the edge rotational transform to approach 1.5. At Phi=0, the unstable m/n=2/3 structure is strongly coupled with a m/n=9/13 term. Negative Phi reduces the edge transform below 1.4 and the m/n=2/3 mode couples with a m/n=5/7 component instead. Positive Phi displaces the edge transform closer to the critical value 1.5 weakening the contribution of toroidal sidebands like m/n=9/13, but deteriating the stability conditions slightly further. Global n=1, n=2 and n=4 modes are basically internal and have smaller growth rates than the n=3 external kink. These structures evolve from interchange-like for n=1 to ballooning-like for n=4.
Bibliographic Reference: An article published in: Journal of Plasma Fusion Research, Vol. 4 (2001), pages 418-421.
Availability: Website of journal publisher: http://jspf.nifs.ac.jp/index-e.html
Record Number: 200316457 / Last updated on: 2003-07-08
Original language: en
Available languages: en