Suppression MHD instabilities by IBW heating in HT-7 Tokamak
In HT-7 tokamak, the m= 2/1 tearing mode can be effectively suppressed by the ion bernstein wave (IBW) when the location of power deposition is near the q=2 rational surface. Off-axis electron heating and greatly increase of electron density was observed, in the meantime, the particle confinement appears to be improved with the increased of the central line averaged electron density and the drop of Da emission. Induced large ne gradients and pressures were spatially correlated with the IBW deposition profile by theoretical calculation >. It is suggested that off-axis IBW heating modifies the electron pressure profile, and so the current density profile could be redistributed resulting in the suppression of the magnetohydrodynamics (MHD) instability. It provides an integrated way for making combined effects on both the stabilization of tearing modes and controlling of pressure profile.