Inductive oscillometry. II. The six-solenoid oscillometer. Non-intrusive, low-frequency diagnostics of a positive-glow plasma

Abstract

For pt.I see ibid., vol.11, p.364 (1978). Details are given of experiments which are of fundamental importance in assessing the correctness of the field difference theory described in paper I. In each series of tests a different model of a new inductive oscillometer is used. This is the six-solenoid contactless device for determining electrical conductivity. The agreement between observation and the predictions of field difference theory, which were tested with this new instrument, has been generally good. In describing the design and operation of the contactless devices the paper provides insight into the novel features of the six-solenoid oscillometer and sets out new approaches to the most commonly reported instrumentation problems which have hitherto restricted the ranges of applicability of these types of conductivity monitor. In addition, a new non-intrusive technique is described for monitoring conductivity in plasmas confined in non-conducting cylinders.