Correlation of Pinch Properties with Minimum Pinch Radius in UNU/ICTP PFF for Different Pressure of Argon Gas

Abstract

In this present work, numerical experiments are performed using the Lee code to examine the correlation of minimum pinch radius (r_min) with pinch energy density (PED), ion number density (N_i), induced voltage (V_max), total radiation power (P_rad) and Joule heating power (P_joule) in UNU/ICTP PFF device when using argon gas at different pressure. The computed results show that at the optimum pressure of 1.0 Torr argon, PED (338 × 10⁹ Jm^-3), N_i (123 × 10²³ /m³), V_max (245 kV), P_joule (114.48 × 10⁸ W) and P_rad (173 × 10⁸ W) reach to their maximum values whilst the r_min reaches to its lowest value of 0.01 cm. At this optimum condition, due to strong radiation cooling effect is found and the excess (P_joule - P_rad) in radiative power of -58.51 × 10⁸ W (negative singe indicates the energy going out from pinch plasma) which is sufficiently enough to cause the radiative collapse in heavier argon pinch plasma. Hence, the excess radiation power would be another reason for the occurrence of radiative collapse beside the critical (Pease-Braginski) current.