A high frequency probe for absolute measurements of electric fields in plasmas. II

Summary form only given. In a previous publication, here called paper I (Torven et al., J. Phys. D: Appl. Phys. vol.28, p.595 (1995)), a new technique to measure high frequency electric fields in a plasma was proposed and tested. Instead of maintaining a high probe impedance and measuring the difference in probe potential, the two electrodes of a double probe were externally connected by a low impedance (50 /spl Omega/) and the current in this external circuit was measured. This current gives, after proper evaluation, a measure of the electric field within the plasma. The technique is useful for frequencies that are so high that it is difficult to maintain a high probe impedance. We have used it up to about 1 GHz. Here this work is continued with the emphasis on the operation of the probe in a plasma. Important parameters are, the following ratios: between the probe wire thickness and the Debye length, between the probe pair separation and the Debye Length, between the wave frequency and the plasma frequency, and between the probe bias and the electron thermal energy.