Behavior of Guarded Probes. Part I. The Affiliated Families of Probe Curves. Part II. The Second Derivative Curves.

摘要

The behavior of probes with guard-electrodes (GP's) is investigated experimentally. The results are described systematically by means of the probe-current profile spanning the voltage plane,with the coordinates V sub p identically equal to probe voltage and V sub G identically equal to guard voltage. Interpretation of the probe curves and their second derivatives is complicated because the fields between the plasma and the GP generally are more complex than those for the single probe. The advantages of GP's for decreasing the secondary effects inherent in the unguarded probe in the vicinity of the space potential point and for finding this point are demonstrated. Generally speaking,the information provided by the parameter V sub G,available in addition to the V sub p of the unguarded probe,is discussed. (Author)