Structure of an extended plasma jet in a vacuum arc in an axial magnetic field

The motion, heating, and ionization of a plasma in a ring anode vacuum arc in an axial magnetic field are studied using a quasi-one-dimensional MHD model. The region between the cathode and anode (a current-carrying plasma jet), as well as the region behind the anode (a current-free plasma jet), is considered. It is shown that, over a long portion of a current-free plasma jet, the electron density and temperature remain high and the ion charge increases substantially due to electron-impact ionization.