Ion charge state distributions in high current vacuum arc plasmas in a magnetic field

We have investigated the charge state distributions of metal ions produced in a high current vacuum arc plasma located in a strong magnetic field. The arc current was varied over the range 200 A to 4 kA and the magnetic field was from zero up to 10 kG. In general, the effect of both high arc current and high magnetic field is to push the distribution to higher charge states-the mean ion charge state is increased and new high charge states are formed. These effects are explained in terms of increased power input (higher plasma temperature) and delayed freezing of the charge state distribution during the plasma expansion process.