Effect of a DC preionization source on energy deposition in a pulsed inductive plasma

Summary form only given. Understanding of the early time formation of inductively coupled pulsed plasmas is a necessary step in producing high power pulsed plasmoid propulsion systems, namely field reversed configuration devices¹. Several circuit models exist for estimating plasma properties but neglect the effect that a preionization source will have on the plasma properties^2,3. Other authors have studies preionization sources but have not performed a detailed parametric study⁴. This paper studies the effect that position and bias voltage of a DC preionization source have on energy coupling to a pulse inductive plasma formed using a theta pinch. Five radial positions and five bias voltages are applied to Argon prefills of 10-1,000 mTorr. Using SPICE⁵ software and established plasma models, an iterative method is used to determine the effective plasma resistance and inductance and are used to determine the energy present in the plasma as a function of time. The greatest amount of energy transferred to the plasma was TBD J occurred with at TBD mTorr with the DC preionization source located at TBD cm with a bias voltage of TBD V. It is observed that energy coupling into plasma increased TBD% as the probe neared the wall of the quartz insulator. Increasing the bias voltage increased plasma energy by TBD%. Increasing Argon prefill pressure past TBD mTorr resulted in reduced plasma energy.