Stirring unmagnetized plasma

Phys Rev Lett. 2012 Mar 16;108(11):115001. doi: 10.1103/PhysRevLett.108.115001. Epub 2012 Mar 12.

Abstract

A new concept for spinning unmagnetized plasma is demonstrated experimentally. Plasma is confined by an axisymmetric multicusp magnetic field and biased cathodes are used to drive currents and impart a torque in the magnetized edge. Measurements show that flow viscously couples momentum from the magnetized edge (where the plasma viscosity is small) into the unmagnetized core (where the viscosity is large) and that the core rotates as a solid body. To be effective, collisional viscosity must overcome the ion-neutral drag due to charge-exchange collisions.