Experimental observation of enhanced plasma loss due to ohmic heating currents in the collisional and intermediate regimes

Experiments are reported using the Culham Superconducting Levitron in which the plasma confinement time has been measured as a function of current induced in the plasma. The regime of collisionality and u/vsub(e) is similar to that in several present-day Tokamaks. The confinement time is found to be proportional to plasma density and inversely proportional to the induced current. It correlates well with u/vsub(e) and rather small values of this ratio are sufficient to reduce the confinement time below the current-free level. There is a good correlation between the loss rate and the amplitude of fluctuations