Observation of the Strong Temperature Gradient in Detached Plasma by PIC Simulation with Monte Carlo Collision

Abstract

In this work, the 1D-3V particle simulation with Monte Carlo collision and cumulative scattering angle Coulomb collision was developed to study the kinetic behavior of the detached plasma. The constant pressure and temperature of the neutral gas box in front of the divertor target were used in the simulation. The simulation was performed with a fixed upstream plasma density n_u ∼ 3 × 10¹⁸ m⁻³ and a modified large Coulomb collision frequency. When the neutral gas pressure is increased, there is a strong decrease in the electron temperature inside the neutral gas box. The electron temperature in front of the divertor target also decreases to below 1 eV, which is one of the conditions for detached plasma.