A method and system for real-time measurement of wide-area plasma density

Abstract

The invention belongs to plasma density diagnosis technology, and specifically discloses a method and system for real-time measurement of wide-area plasma density. A system composed of a laser light source, two frequency doubling crystals, a modulator, a data processing unit, etc. The light source is converted into two beams of light of different frequencies coaxially transmitted by frequency doubling. The modulation technology and signal transfer technology are used to identify the phase difference of the two beams of light through the measured medium, and record and output in real time. This phase difference is the same as The density of the medium to be measured is related to the real-time measurement result of the density, the measurement range is wide, the measurement beam deflection is small, and the plasma electron density measurement method and system without vibration influence.

Description

technical field [0001] The invention belongs to plasma density diagnosis technology, in particular to a method and a measurement system for real-time measurement of wide-area plasma density. Background technique [0002] In low temperature (such as linear device) and high temperature (such as tokamak device) plasma physics research, the real-time measurement of plasma electron density is the most basic and one of the most important diagnostic systems for device operation and physical research. Especially during the operation of the device, it is necessary to continuously obtain density information for density feedback control, which requires a real-time signal output with a certain time resolution for the measurement system. [0003] Usually, the measurement of plasma electron density adopts a two-beam interference method: one beam of light passes through the plasma, and the other beam does not pass through the plasma, and the phase difference of the two beams of light is us...

AI Technical Summary

Problems solved by technology

Due to the limited wavelength of the laser that meets the measurement conditions, it is generally difficult to use a laser interferometer system to meet the density measurement of low temperature and high temperature plasma at the same time

For example, for plasma with lower density (such as tokamak high-temperature plasma, 10 18 m -3 20 m -3 ) usually uses far-infrared laser, the laser wavelength is longer, and the refraction effect is higher. When the density changes too fast, it is easy to lose the number of fringes and make the measurement fail; for plasma with higher density (such as low-temperature plasma in linear devices, 10 19 m -3 22 m -3 ) usually uses short-wavelength lasers, but the detection wavelength is short, and the vibration effect of the system cannot be ignored. Two complex interferometer systems composed of two independent lasers must be used to work normally.

Images