In the HT-7 tokamak, the m = 2/n = 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 electron density broadening have been observed. In the meantime, the particle confinement is improved with an increase in electron density and a drop in Dα emission. The induced large electron density gradients and electron pressure gradients can be spatially correlated with the IBW deposition profile via theoretical calculation. It is suggested that off-axis IBW heating modified the electron pressure profile and the current density profile can be redistributed, thus resulting in the suppression of the magnetohydrodynamics (MHD) instability. It provides an integrated way for both the stabilization of tearing modes and controlling pressure profiles.
Simulation of density fluctuations before the L-H transition for Hydrogen and Deuterium plasmas in the DIII-D tokamak using the BOUT++ code