Measurements and modeling of ion and neutral distribution functions in a partially ionized magnetically confined argon plasma

The influence of ion-neutral collisions on the ion and neutral distribution functions in low field radio frequency (rf) heated argon discharges was investigated. In order to obtain some insight into the ion heating mechanism and to resolve apparent inconsistencies between probe and spectroscopic measurements of the ion temperature, the measurements were initially undertaken. It was found that the measurements of the ion distribution function reveal a substantially elevated fraction of low energy particles, associated with charge exchange and ionization. The ion and neutral distribution functions were modeled using the Boltzmann equation including, collision operators for ion-ion and ion-neutral collisions, ionization, heating and particle loss.