Experimental Stabilization of Interchange Mode by Surface Line Tying

Experiments are performed in an attempt to stabilize the magnetic-curvature-driven interchange instability (mirror flute mode) using a $Q$-machine plasma. The stabilization method consists of applying a tenuous plasma blanket, which is line tied to the end wall, around a flute-susceptible higher-density core plasma which has no electrical contact to the wall. By controlling the degree of line tying between the blanket and the wall, the stabilizing effect of surface line tying is demonstrated.