The Influence Of Secondary Electron Emission On The Sheath And Near Wall Conductivity In Stationary Plasma Thruster

The stationary plasma thruster (SPT) is the most widely used electrical propulsion device, which is investigated in our country for future use. It is very necessary to study the complicated phenomenon happened in the channel to understand the principle of the device. There is complicated correlation between the plasma region, the wall and the sheath, which is a transitional region between the plasma region and the wall. This paper is focused on the correlation between the three regions. Based on the introduced secondary electron emission (SEE) model, we studied the effect of radial ion flux and material character on the sheath and the near wall conductivity (NWC).When collide with the channel wall, electrons can knock out secondary electrons, which is the so called SEE phenomenon. SEE plays a very important role in the operation of the device and influences the sheath especially, therefore, a proper SEE model itself is meaningful and also very important for sheath calculation. After investigating the SEE phenomenon and models in existence carefully, we introduced an advanced SEE model, which is more reasonable compared with the existent models.As a fundamental physical problem, plasma sheath greatly influences the complex physical phenomenon in the channel, however it is very difficult to investigate it by experiments, so we introduce a one-dimensional kinetic model of the sheath, and the boundary condition on the wall position is the SEE model. Based on the model, we have analyzed the effect of radial ion flux and material character on the sheath. At the same time, we analyzed the sheath oscillation briefly.The potential along the axial position is decided by the electron conductivity, the NWC is a very important kind of which because the area of the channel is comparatively large. Using the theory of a single particle orbit combined with Monte Carlo simulation, the near-wall conductivity current density is calculated. Based on the model, we analyzed the effect of sheath potential, the secondary electron temperature on the NWC. When taking into account the sheath calculation, we analyzed the effect of radial ion flux, material character on the...