Method of the electron distribution function calculation in a problem of the kinetic rarefied plasma plume modeling

A problem related to the rarefied plasma plume of the stationary plasma thruster (SPT) is considered in the paper. The consideration is conducted fully in terms of kinetics, namely, distribution functions are introduced to describe motion of every plasma component. The system of kinetics equations for the distribution functions should be solved in combination with the Maxwell’s equations. The paper discusses methods for solving the stated problem.

Methods for Assessing Parameters of the Stationary Plasma Engine Plume Multifractional Model Based on the Results of Probe Measurements

Methods are presented for determining parameters of the stationary plasma thruster (SPT) multifractional conical plume model using the electrostatic probing analyzer braking characteristics with retarding potential. Processing is carried out in three stages. At the first stage, braking characteristics are smoothed using the cubic splines. Node initial position is determined by the piecewise linear approximation nodes. Then, optimization problem is being solved, and node position is found, spline minimum deviation from the experimental curve is achieved in the absence of points with positive derivative. At the second stage, plume ions are divided into monoenergetic fractions. Division is carried out by the inverse function method with respect to the plume ions integral distribution function. At the third stage, fraction angular characteristics are smoothed together. To ensure constancy of the fraction current density total values, which could be violated with separate smoothing, special functions are introduced to separate the fractions. These functions divide the plume ions into two parts according to the retarding potential value corresponding to the fraction boundaries. Separation functions are being smoothed, and a set of smoothed angular characteristics of each fraction is obtained using these functions. In this case, the total fraction current density is not changing. Obtained distributions are used as parameters of a plume multifractional conical model suitable for engineering analyzes of the stationary plasma thruster on a spacecraft. Smoothing eliminates irregularity in angular and energy distributions caused by the measurement error and makes it possible to exclude probable artifacts appearing from analyzing results of the stationary plasma thruster plume impact on the spacecraft elements and systems

Hybrid model of a stationary plasma thruster

A mathematical model is proposed for studying the processes in a stationary plasma thruster (SPT) taking into account the ionization of the working substance - Xenon, based on the hybrid equations of electromagnetic hydrodynamics (EMHD) of the plasma. The 1D2V case of plane symmetry is considered in detail, for which a numerical algorithm for investigating solutions of hybrid EMHD equations is constructed, based on the method of macroparticles. The solution of a number of fundamental issues is given: the calculation of average values, interpolation, construction of the initial distribution of macroparticles, the choice of boundary conditions for the electric field, etc. The results of calculations with and without taking into account the induction fields in the SPT are presented.