Dynamic Stabilization by Modulated Toroidal Current on the HT-7 Superconducting Tokamak

The technique of toroidal current modulation has been successfully used in suppressing magnetohydrodynamic (MHD) perturbations effectively on HT-7 superconducting tokamak. When the ratio of amplitude of plasma modulated current ΔI_p versus the equilibrium plasma current I_p0 is about 12-30%, the resonance surface is moved outside the island width, the suppression of MHD perturbations is observed. The disruption induced by tearing mode instability is delayed or avoided. Different formats of frequency modulated are compared.