Energy Analysis of a Pulsed Inductive Plasma Through Circuit Simulation

Abstract

Current profiles of a cylindrical ringing thetapinch are compared with SPICE simulations of an established circuit model and a least squares estimate is performed to determine plasma resistance and inductance for argon, hydrogen, and xenon plasmas with prefill pressures ranging from 10 to 100 mTorr. Plasma resistance is found to vary from 25.8 to 51.6 mQ with the lowest resistance occurring at 10 mTorr. Argon and xenon follow a similar trend with the xenon resistance averaging 4.2-mΩ (12.3%) larger than argon from 40 to 100 mTorr. Hydrogen resistance is found to increase rapidly as prefill pressure increases above 40 mTorr. Calculated plasma resistivity of 214-429 Ω-μm agrees with established literature. Plasma inductance varies from 41.3 to 47 nH and is minimized at 30 mTorr for argon and hydrogen, whereas xenon inductance is minimized at 20 mTorr. Hydrogen yields the highest inductance, averaging 1.9 nH (4.5%) more than argon over the pressure range tested. Temporal evolution of the energy partitioning into capacitive, inductive, and resistive loads is presented. Plasma inductive energy is found to be maximized when discharge current reaches its peak negative value of -23.5 kA. Xenon shows the greatest amount of inductive energy storage with a peak of 6.4 J (8.1%) of the initial 79.2 ± 0.1 J while argon dissipates the least energy through ohmic losses at most pressures. Hydrogen has the least inductive energy storage at all pressures and greatest ohmic losses above 60 mTorr. Xenon presents the largest ohmic losses over the 10-60-mTorr range.