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In this paper, an inductively coupled pulsed plasma source with an operating frequency of 29 kHz is described. Using a series resonance circuit with a load capacitance of 12 [micro]F and large diameter (approximately 20 cm) induction coils surrounding a spherical discharge vessel, a discharge plasma was produced and investigated in a pressure range of 0.1 to 100 Pa. Pulsed coil currents reached a maximum value of 9.6 kA with current rise times of 1.8 kA/[micro]s while achieving an energy coupling efficiency of 80% between the driving circuit and the plasma. Pulsed-power peak values reached more than 800 kW. Moreover, the spectroscopic diagnostic revealed a high fraction of ionized particles and an emission spectrum in the near UV domain. Electron densities reached peak values of [10.sup.21] [m.sup.-3]. By using a fast camera system, the initiation of the discharge was investigated. The ignition of the discharge along an azimuthal path was documented, showing evidence of an entirely inductive plasma initiation without capacitive coupling. Index Terms--Diagnostics, plasma dynamics, plasma sources.

In this paper, the design, construction, and test procedure of a closing-switch prototype based on thyristors are described. In particular, details are given about the design criteria and the triggering board architecture, which is a high-side-biased self-supplied unit using electrical energy derived from a local snubber network for the gate drive. The structure guarantees a hard firing gate pulse for the required high-dI/dt application. Furthermore, the results of the prototype tests are presented and discussed. The stack assembly has a holding voltage of 6.5 kV and is used for switching a series resonant circuit with a ringing frequency of 12 kHz for a pulsed inductive plasma source. Maximum current amplitudes of 13 kA and pulse energies of more than 600 J were switched during the test procedure. [ABSTRACT FROM AUTHOR]