Probe and method for measuring plasma space potential by aid of bias currents

Abstract

The invention discloses a probe and method for measuring plasma space potential by the aid of bias currents. The method includes: acquiring relative coupling potential by coupling the spherical probe with plasma around the spherical probe; allowing 'suspension type' constant-current source circuit to applying the bias current to the probe; internally installing a high-impedance coupling potential detection circuit and a bias current circuit in the spherical probe; allowing a signal processing unit to process coupling potential signals of the probes and provide control voltage signals to the bias current. The equivalent mode of application of the bias current is adopted for the probe, floating point potential of the probe is changed and approaches to plasma space potential around the floating point potential; plasma parameters are diagnosed according to the Langmuir probe, the initial value of the applied bias current is acquired from calculation, and rapid convergence of the bias current value is realized; the plasma space potential is finally acquired through final measurement with a continuous bias current increasing method; thermionic emission of the emission probe and space-charge effect thereof can be avoided, and measurement precision of the probe on the plasma space potential can be improved.

Description

technical field [0001] The invention relates to the technical field of measuring plasma space potential and environment detection, in particular to a probe and a measuring method for measuring plasma space potential by using a bias current. Background technique [0002] Plasma space potential is an important parameter for studying, creating, diagnosing, and characterizing plasma environments. It is an early, simple and traditional method to determine and measure the plasma space potential by using the "inflection point" (where the second derivative is zero) of the scanning voltammetry characteristic curve using the Langmuir probe. Both theoretical and experimental studies have shown that the measurement The accuracy of the method is low, and its application is limited especially in the high temperature and high density magnetic fluid plasma environment. It is a commonly used and more effective method to determine and measure the plasma space potential by using the "inflecti...

AI Technical Summary

Problems solved by technology

It is a commonly used and more effective method to determine and measure the plasma space potential by using the "inflection point" of the scanning volt-ampere characteristic curve by using the emission probe. This measurement method has less disturbance to the environment and higher precision. It can also be applied in the plasma environment of strong magnetic field, electron beam or ion beam, but theoretical and experimental studies have shown that its thermionic emission sheath (or space charge effect) affects the precise measurement of the plasma space potential by the probe

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