Ion flows from a beam-plasma discharge

The results of measurements of the energy distribution function of ions escaping from a beam-plasma discharge are compared with the data from probe measurements in the discharge region. It is shown that, on the discharge axis, there is a region with a higher degree of ionization, whose position depends on the external parameters, in particular, on the gas pressure. The mean energy of the ions that leave the plasma from the outside of this region is determined by the potential of the plasma column. Inside the region with a higher degree of ionization, there is an additional mechanism for ion acceleration; as a result, the energy of the ions that leave the plasma from this region is higher than the energy of the electrostatically accelerated ions by a factor of 1.5 to 5. The results obtained show promise for creating a plasma-processing reactor with controlled ion parameters for the purposes of treating materials for microelectronics.