Voronovsky D. Determination of the magnetic field topology for the purpose of optimizing the parameters of the Hall thruster - a qualifying scientific work on the rights of a manuscript

Electric propulsion systems are widely used on board satellites to solve the problems of orientation and stabilization, maintaining and changing the orbit, braking the satellite after the completion of the mission. With the expansion of the CD range, the significant increase in total momentum also emphasizes the need to develop high-performance CDs. It is well known that the operational resource of the HD is determined by the amount of time during which the engine can operate before the plasma in the channel damages the magnetic system. After complete erosion of the dielectric output from the discharge channel, the ion plume interacts with the inner and outer magnetic poles and causes progressive erosion of the magnetic conductor. A new magnetic topology called "magnetic shielding" (ME) has been described to dramatically reduce channel erosion, potentially eliminating this HD failure mode. The purpose of the work is to determine the possibility of increasing the traction-energy and resource characteristics of the HD by optimizing the parameters and topology of the magnetic field in the engine; development of recommendations for the design of magnetic systems of prospective HDs. The use of modern programs allows determining the azimuthal distribution and configuration of the magnetic field in the acceleration channel and in the peripheral zone of the engine, as well as obtaining results that are close to real ones. In this regard, in this work, the method of mathematical modeling was chosen as a research method for conducting research on the magnetic field of HD. In the program, the user must create the geometry of the object under study, the assignment of the properties of the materials, the method and the accuracy of the calculation. Thus, taking into account the specifics of the researched objects, before conducting research, there was a need to practice the methodology of modeling magnetic systems of HD in ANSYS Maxwell. Formulated tasks: 1. conducting an analysis of the advantages and disadvantages of existing structures and parameters of magnetic systems of HD; 2. development and verification of the methodology for calculating two-dimensional and three-dimensional calculation models of magnetic systems taking into account the saturation of the magnetic field; 3. conducting an analysis of the relationship between the geometric characteristics of the erosion zones of the walls of the discharge chambers of motors with the magnitude and topology of the magnetic field in the discharge channel of these motors and the prediction of the geometric characteristics of the erosion zone based on the results of calculating the parameters and topology of the magnetic field; The scientific novelty of the work is as follows: 1. the calculation of the construction of models of magnetic systems of HD has been improved, which allows to simplify modeling and calculations and minimize the calculation time; 2. the quantitative relationship between the magnitude and configuration of the magnetic field, engine operation parameters and length, and the position of the ionization and acceleration layer in the HD discharge channel, which determine the boundaries of the erosion zones of the discharge chamber walls, is determined, namely: • it was established that the boundaries of the erosion zones on the outer and inner walls of the discharge chamber from the anode side are at the intersection of one "boundary" line of force of the magnetic field with the walls, the discharge voltage, the shape of the magnetic lens, the amount of induction and the material of the discharge chamber; • the position of this "limit" line of force is determined by the value of k×Brmax along the middle line of the discharge chamber (LC). 3. it is shown that increasing the traction efficiency and reducing the size of the erosion zone of the walls of the discharge chamber in the engine is achieved due to the optimization of the parameters and topology of the magnetic field.