Research On The Electromagnetic Properties Of Plasma Based On Microwave Reflection Method

Plasma can be equivalent to a kind of media, the effective dielectric constant determines its characteristics. Electron density and collision frequency are the main characteristics of plasma parameters. Microwave dielectric electric parameter measurement method can be used to study the plasma characteristics. The plasma characteristic parameters are analyzed by reflection method analysis in this paper.The main contents are the following:1. The reflection characteristics of flat and cylindrical plasma is analyzed in this thesis. The expression of the reflection coefficient of electron density and collision frequency is discussed by using the geometrical optics method of flat and cylindrical plasma. The plasma reflection coefficient of different sizes is simulated in different frequency, different electron density and different collision frequency. It can be seen that different electron density corresponding to the same reflection coefficient at the same plasma thickness and incident wave frequency, collision frequency.2. The shock tube electromagnetic model is built by electromagnetic field. Reflection coefficient is deduced on the expression of the electron density and collision frequency. With the theory of transmission line, equivalent circuit model is established, reflection coefficient is also deduced by this way. The same reflection coefficient can be got by the two methods at the same electron density and collision frequency, transmission line method is used to analysis the plasma characteristic parameters.3. For solving the multi-value problem of plasma characteristic parameters, using genetic algorithm, optimization to get the sight answer.4. Through the experimental data, the plasma electron density and collision frequency is calculated out.Dot frequency reflection method is used to calculate the plasma characteristic parameters in this paper, the measurement of plasma electron density range is 10¹⁰¹0¹²e/cm³, the collision frequency range is 10⁹¹0¹¹HzHz, plasma duration is about hundreds of microseconds.