Termination of a magnetized plasma on a neutral gas: The end of the plasma
C. M. Cooper and W. Gekelman
Accepted
Experiments are performed at the Enormous Toroidal Plasma Device (ETPD) at UCLA to study the Neutral Boundary Layer (NBL) between a magnetized plasma and a neutral gas along the direction of a confining magnetic field. This is the first experiment to measure plasma termination within a neutral gas without the presence of a wall or obstacle. A magnetized, current-free helium plasma created by a Lanthanum Hexaboride (LaB$_6$) cathode terminates entirely within a neutral helium gas. The plasma is weakly ionized ($n_e/n_n \sim$ 1\%) and collisional $\lambda_n