Influence of current instabilities on the parameters of the vacuum arc plasma jet

The influence of the Buneman instability on the parameters of a current carrying plasma is investigated. By using the quasi-linear approximation the analytical expressions which connect the plasma parameter changes and the turbulent electrical conductivity with the energy of the unstable electrostatic field fluctuations were obtained. The latter is expressed by the plasma supercritically. The experimental data of the arc discharge in an extended gap are analyzed. It is shown that the changes of the electron temperature and potential drop can be explained by this instability.