Characteristics of Upstream and Downstream Plasma Parameters from Langmuir Probes and Visible Spectrometers in the D-Module of GAMMA 10/PDX

Abstract

Plasma parameters in the upstream and downstream regions in the divertor simulation experimental module (D-module) of the tandem mirror plasma device GAMMA 10/PDX were conducted using Langmuir probes. The detached plasma was produced using hydrogen puffing. In the upstream region, the electron temperature decreased from 30 to 7 eV, and the electron density increased. On the other hand, rollover of n_e at the V-shaped corner was observed in the downstream region. Increasing H_α/H_β at the corner of the V-shaped target was attributed to the molecular activated recombination processes. H_α/H_β in the downstream region was different from that in the upstream region. Therefore, the ionization front appeared in the upstream region of the D-module.