M.Sc Thesis


M.Sc StudentShlomy Shitrit
SubjectInvestigation of Improved Hall Thruster Configuration
for Low Power Operation
DepartmentDepartment of Aerospace Engineering
Supervisors Full Professors Natan Benveniste
Dr. Joseph Ashkenazy


Abstract

The Hall thruster is a rocket engine which generates its thrust by accelerating a plasma jet by the combined operation of perpendicular electric and magnetic fields in a coaxial channel. The work deals with the performance of low power (200-300 W) Hall thrusters. When a given Hall thruster is operated at power levels below its nominal operating power, its performance tends to degrade. The standard approach to overcome this problem is to scale down the thruster. However, as the analysis has shown, this approach is limited by magnetic material and circuit properties. Moreover, the main drawback of down-sized Hall thrusters in this power range is the sharp drop in their operating lifetime compared to larger size thrusters. As a consequence, the approach adopted in this work for Hall thrusters in the 200-300 Watts range is to try to improve the propellant utilization by geometric and magnetic modifications but without scaling down the thruster. A straightforward implementation of this approach, to extend the channel length, was investigated experimentally. Results indicate that in the 200-350 W input power range, higher thrust, specific impulse and efficiency are achieved. As part of this investigation, an improved laboratory Hall thruster was designed and constructed. In order to improve the thrust measurement accuracy a new calibration system, was designed and built. The effect of the magnetic field distribution on the thruster performance at reduced mass flow rates was also examined. This part of the work included a preliminary investigation of a novel idea of a new type of Hall thruster.