Plasma velocity measurement method and system

Abstract

The invention discloses a plasma velocity measurement method and system. The method comprises the following steps: calibrating a frequency stating point of a macroscopic velocity of a flow field plasma to be measured; obtaining a curve of fluorescence signal intensity changing along with a laser frequency by performing measurement on the flow field plasma to be measured based on laser induced flourescense; and according to a measurement result, obtaining a Doppler broadening effect component through separation, and obtaining actual velocity distribution of the flow field plasma to be measured through conversion by taking the frequency starting point as a reference. According to the invention, plasma velocity measurement is carried out based on the laser induced flourescense, an ion motion velocity is measured through measuring a Doppler effect excited when ions are stimulated in a flow field to be measured, the noncontact type measurement technology is brand new, disturbance to the flow field to be measured does not exist, influences of electromagnetic interference widely existing in an electric thruster are eliminated, and the apparatus and system have the advantages of high precision, high interference immunity and wide applicability, thereby being widely promoted and applied.

Description

technical field [0001] The invention relates to the technical field of electric propulsion plasma diagnosis, in particular, to a method and system for measuring plasma velocity. Background technique [0002] In the field of space vehicle jet propulsion technology, electric thrusters that accelerate ions by electrostatic force or plasma by Lorentz force occupy an increasingly important position, and there is still a lot of room for technological development. The working fluid injected by the electric thruster is low-temperature plasma, which has a macroscopic velocity of 15000m / s-40000m / s or even higher, and at the same time, the pressure is relatively low, generally only a few Pa to hundreds of Pa. In order to evaluate the characteristics of thrust vector, working fluid utilization efficiency and plume pollution, it is necessary to accurately measure the spatial distribution of the jet's macroscopic velocity. [0003] So far, the measurement of the macroscopic velocity dist...

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Problems solved by technology

[0004] The invention provides a plasma measurement method and system to solve the flow field disturbance caused by the contact measurement of the existing Mach probe and the measurement accuracy is limited by the magnetic field, and the introduction of nanoparticles by the NPLS method cannot be directly applied to the electric thruster flow. Technical Issues of Field Plasma Velocity Measurements

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