Investigation of large-area multiarc pulsed ion source plasma parameters

Using plasma probes of different geometries and spectroscopic methods, crucial plasma parameters like electron temperature, plasma density and plasma potential were measured on a multiarc large area ion source (MAIS). MAIS is a pulsed source of plane geometry and circular circumference, in which the ion emitting plasma is built up by the synchronous ignition of an array of 180 individual discharge units. The total current through all discharge units was varied in the range of 100-300 A. The pulse duration was of the order of z=30 A and the applied acceleration voltage U=10-20 kV. Plasma parameters assessed by these measurements were as follows: electron temperature near the anode (extractor) grid 10-30 eV; in the spark region ⩾4 eV. The electron density n, near the anode grid is in the range of 10¹¹ cm^-3 (depending on discharge current, the radial coordinate and on the potential of the anode grid), in the spark region ⩾5×10 cm^-1. The plasma potential lies in the range of 50-70 V