Reconstruction of Ionization Density Distribution in Hall Thruster Channel from Ion Energy Spectrum of Plasma Jet

Propellant ionization in the Hall thruster discharge channel is a significant process and has strong influence on the thruster＇s efficiency. In this work, the functional relation has been established between the ionization density distribution and the function of the ion energy distribution through the basic equations governing the ion flow in the Hall thruster channel and the method achieved for reconstructing the ionization density distribution inside the channel by ordinary plasma diagnosis of the potential distribution and ion energy spectrum of the plasma jet. The ionization density distributions of single and double charged ions in an ATON-thruster channel have been reconstructed according to the experimental data of the potential distribution along the axis of the channel and the ion energy spectrum of the plasma jet. The agreement between the calculation and experimental results of the percentage of double charged ions proves the validity of our method achieved in this work.

Study on the Two-Dimensional Density Distribution for Gas Plasmas Driven by Laser Pulse

We perform an experimental study of two-dimensional（2D） electron density profiles of the laser-induced plasma plumes in air by ordinarily laboratorial interferometry. The electron density distributions measured show a feature of hollow core. To illustrate the feature, we present a theoretical investigation by using dynamics analysis. In the simulation, the propagation of laser pulse with the evolution of electron density is utilized to evaluate ionization of air target for the plasma-formation stage. In the plasma-expansion stage, a simple adiabatic fluid dynamics is used to calculate the evolution of plasma outward expansion. The simulations show good agreements with experimental results, and demonstrate an effective way of determining 2D density profiles of the laser-induced plasma plume in gas.