using a Reciprocating Langmuir Probe.*

The Hybrid Illinois Device for Research and Applications (HIDRA) has previously been reported to operate with electron temperatures as high as 20 eV and electron densities up to 1.0×10¹⁸ m^-3, and the existence of hollow plasmas and fast electron populations has been noted. For proper usage of the mentioned stellarator to conduct future Plasma Facing Components (PFC) with liquid lithium experiments, the Reciprocating Langmuir Probe (RLP) is used to verify the spatial plasma parameters created in HIDRA. The process is performed using He and H₂ plasmas at 20%, 50%, and 90% of 6 kW magnetron heating (at 2.45 GHz), under pressures of 4.0×10^-5, 3.5×10^-5, and 2.9×10^-5 Torr. As the data analysis has proceeded so far, He plasmas in general and H₂ plasmas at higher power rates have illustrated IV-curves (current vs. voltage curves) with an invisible “knee”, which poses a problem in finding the plasma potential necessary to obtain electron temperatures and densities. Spectroscopy is a second diagnostic used to obtain the plasma’s spatial profile, where its derived electron temperatures and electron densities are used to confirm the measurements made by the RLP. T_e and n_e profiles are critical in understanding plasma behavior and impurity transport. This paper will present the latest temperature and density profile results from HIDRA.