Plasma Current Profile During Current Reversal in a Tokamak

Alternating current operation with one full cycle and a current level of 2.5kA have been achieved in the CT-6B tokamak. The poloidal magnetic field in the plasma is measured with two internal magnetic probes in repeated discharges. The current distribution is reconstructed with an inversion algorithm. The inversed current first appears on the weak field side. The existence of magnetic surfaces and rotational transform provide particle confinement in the current reversal phase.