Electrothermal plasma source as a high heat flux simulator for plasma-facing components and launch technology studies

摘要

An electrothermal plasma source "SIRENS" has been designed, constructed, and operated (over 450 shots) to produce high density (>1025/m3), low temperature (1–3 eV) plasma formed by the ablation of the insulator (Lexan, C16 H14 O3) with currents of up to 100 kA and energies up 15 to kJ. Switchable capacitor modules allow for higher energy inputs (30 kJ) and longer pulse lengths (0.1–1.0 ms with pulse forming network). The plasma flows through a cylindrical barrel, situated along the axis of a pulsed magnet, which can produce a parallel magnetic field (up to 16 T) over 8 msec pulse length. The source heat flux (up to 90 GW/m2 over 100 μsec pulse) and the diagnostics arrangements (electrical, magnetic, optical, heat flux, pressure, materials) are adequate for various applications (plasma-matter interaction; simulation of thermal quench phase of plasma disruption in fusion tokamaks; simulation of pulsed heat loading conditions of plasma-driven launchers; ablation-controlled arcs; plasma switchers). Different materials (metals, alloys, coated materials, insulators and graphite grades) have been exposed to the high heat flux in SIRENS, where comparative erosion behavior was obtained. Vapor shield phenomena has been characterized for different materials, and die energy transmission factor through the shielding layer is obtained. The magnetic field is produced parallel to the surface to cause a decrease in the turbulent energy transport through the vapor shield to provide further reduction of the surface erosion (magnetic vapor shield effect).