Thermionic emission of a tungsten surface in high heat flux plasma: PIC simulations

The surface temperature of a tungsten facing hot hydrogen plasma is evaluated, thanks to 1d/3v particle-in-cell simulations in floating wall conditions. At each iteration, the heat flux cathode equalized with outgoing one, which due thermionic emission, radiation, and conduction through wall. thermal conductivity chosen within range 35–160 W m−1 K−1 different order take into account condition. A transition from cold one arises for critical conductivity, whose value depends on parameters. This very abrupt leads space charge limited regime where current penetrating has reached its maximal about three times Bohm current. Changing initial conditions code, more particularly, timing electron can lead final temperature. history effect associated hysteresis are evidenced by means fluid calculations, good agreement simulation results as well previous experimental measurements.