Diagnostic system and method for non-uniform plasma electron density

Abstract

The invention provides a diagnostic system for non-uniform plasma electron density, including the following parts: a plasma generator, disposed in front of the calibrator; an ultra-wideband antenna, including a receiving antenna and a transmitting antenna disposed on the same side of the plasma generator; a time domain narrow-pulse source, connected to the transmitting antenna; a high-speed sampling digital oscilloscope, connected to the transmitting antenna and the receiving antenna, and used for recording and processing a transmitting signal of the transmitting antenna and a receiving signalof the receiving antenna; and a programmable power supply system, respectively connected to the time domain narrow-pulse source, the high-speed sampling digital oscilloscope and the plasma generator,and used to trigger the time domain narrow-pulse source, control the discharge power of the plasma generator, and record different discharge power states of the plasma to obtain basic plasma parameters under different discharge states. The system provided by the invention has the advantage of simulating a more accurate environment of super-sonic target surface plasma sheath, and having high testefficiency and low test cost.

Description

technical field [0001] The invention relates to the technical field of microwave testing, in particular to a diagnostic system and method for non-uniform plasma electron density. Background technique [0002] Plasma refers to the aggregated state of matter containing a large number of positively and negatively charged particles with approximately equal numbers of charges. Plasma is generated mainly through energy transport, which causes charge transport. When particles with sufficient energy collide with gas molecules, electrons and ions are generated, thereby forming a plasma. During the high-speed flight of a hypersonic vehicle, the extremely high temperature on the surface will ionize the gas molecules, thereby forming a plasma, which covers the surface of the vehicle to form a plasma sheath. The plasma sheath has an extremely high electron density, which will attenuate the power of electromagnetic wave propagation, resulting in distortion of communication and detection ...

AI Technical Summary

Problems solved by technology

However, the plasma parameters obtained by spectroscopy are limited, and it is necessary to determine the composition of the discharge gas and calibrate it with a known standard light source. The process is complicated and can only measure the plasma environment in a transparent cavity made of glass and other materials, and the plasma discharge temperature is not suitable. Too high, few conditions apply

[0005] In the past, the research on the diagnosis of plasma electron density mainly focused on the probe method and optical method. Although there is a certain basis for the diagnosis of plasma electron density, the probe method is not suitable for diagnosis in a high-pressure environment. The "sheath expansion effect" has a significant impact on the results. Using the probe method to diagnose the plasma electron density requires consideration of the test environment and selection of a suitable theory to calibrate the probe data, which has certain limitations.

However, the plasma parameters obtained by spectroscopy are limited, and it is necessary to determine the composition of the discharge gas and calibrate it with a known standard light source. The process is complex and can only measure the plasma environment in a transparent cavity made of glass and other materials. High, few conditions apply

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