Experimental investigation on high heat flux plasma parameters of HIT-PSI device in argon discharges

Researches on plasma-facing materials/components (PFMs/PFCs) have become a focus in magnetic confinement fusion studies, particularly for advanced tokamak operation scenarios. Similarly, spacecraft surface materials must maintain stable performance under relatively high temperatures and other harsh plasma conditions, making studies of their thermal and ablation resistance critical. Recently, a low-cost, low-energy-storage for superconducting magnets, and compact linear device, HIT-PSI, has been designed and constructed at Harbin Institute of Technology (HIT) to investigate the interaction between stable high heat flux plasma and PFMs/PFCs in scrape-off-layer (SOL) and divertor regions, as well as spacecraft surface materials. The parameters of the argon plasma beam of HIT-PSI are diagnosed using a water-cooled planar Langmuir probe and emission spectroscopy. As magnetic field rises to 2 T, the argon plasma beam generated by a cascaded arc source achieves high density exceeding 1.2×10²¹ m⁻³ at a distance of 25 cm from the source with electron temperature surpassing 4 eV, where the particle flux reaches 10²⁴ m⁻²s⁻¹, and the heat flux loaded on the graphite target measured by infrared camera reaches 4 MW/m². Combined with probe and emission spectroscopy data, the transport characteristics of the argon plasma beam are analyzed.