Experimental confirmation of stable, small-debye-length, pure-electron-plasma equilibria in a stellarator

Abstract

The creation of the first small-Debye length, low temperature pure electron plasmas in a stellarator is reported. A confinement time of 20ms has been measured. The long confinement time implies the existence of macroscopically stable equilibria and that the single particle orbits are well confined despite the lack of quasisymmetry in the device, the Columbia non-neutral torus. This confirms the beneficial confinement effects of strong electric fields and the resulting rapid E × B rotation of the electrons. The particle confinement time is presently limited by the presence of bulk insulating materials in the plasma, rather than any intrinsic plasma transport processes. A nearly flat temperature profile is seen in the inner part of the plasma. © 2006 The American Physical Society.