Research On The Detection Of Plasma With Dielectic Resonator

Plasma detection is an important part of plasma theory. With the increase in use of plasma, new requirement has been put forward in plasma diagnostic. New detected methods rise in response to diverse applications. Plasma diagnostic is mainly refers to detecting characteristic parameters of plasma, including electron density, electron temperature, resonant frequency, etc. Currently, methods to detect plasma can be clarified into contacted types and non-contacted types. This subject stems from a horizontal project of a research institute, who requires the diagnostic system have small size, light weight, real time, reliability and accuracy. To this end, research that use dielectric resonator to diagnose plasma is carried out in this thesis.Dielectric resonator is a kind of simple structure, small volume, low cost of the test system. Dielectric resonator method is a non-contact detection method, so it will not produce interference to the original system and reduce the system error which made by detection equipment.Firstly, physical characteristics of plasma are deeply studied and analyzed in this thesis. Through introducing plasma physical parameters and clear their meaning, the interactions between plasma and electromagnetic wave can be deduce. when the incident electromagnetic wave is different, the plasma have different features,which can provide ideas for the design of dielectric resonator.Secondly, according to the theory of dielectric resonator knowledge, plasma detection model is established. This paper proposes a layered testing model, the electromagnetic field in different areas was analyze strictly through the open waveguide method, and set up the characteristic equation. In this way, plasma electron density can be deduced. The layered model has an error range closed to4.2×10^-6, which is verified by a theory analysis.Thirdly, on the base of the above theory, this paper proposes a dielectric resonator working in C band, which realizing plasma detection in 10¹⁷ m^-3 density range. Choosing the fluorescent lamp as plasma source to fulfill the system integration. Based on MATLAB, the test software is written.Finally, experimental data are analyzed. After discussing the source of error, this study suggests improvements on the system. Based on concluding the deficiency existing in the dielectric resonator system, the thesis provide some suggestions for further research.