Plume Control of a Cusped Field Thruster
The cusped field thruster uses several permanent ring magnets of alternating polarity to create a multistage cusp magnetic topology. It has demonstrated a long lifetime because of reduced plasma losses to the discharge channel surface. However, the high beam divergence problem has not been solved in this type of thruster. The purpose of this technical note is to describe a plume control method to reduce its plume angle. The results show that the magnetic field intensity in the plume region and the shape of the last separatrix have great influence on plume divergence.
Experimental Study of HollowAnode Position Effect on Multistage Cusped Field Thruster IEPC-2015-407 / ISTS-2015-b-407
The performance characteristics of cusped field thruster are strongly associated with the anode process. In order to enhance the working gas ionization rate and diffuse anode centralized heat, a magnetic conductive hollow anode was designed. Three different anode positions were studied, where the anode surface was -8, 0 and 8 mm to the first magnet surface. The magnetic field was simulated by FEMM and the performance was tested in a vacuum system. By providing and analyzing experimental data of anode current and oscillation, thrust, anode efficiency and specific impulse, certain patterns can be found that how does the ionization rate is influenced by different anode positions. Possible explanations for increased ionization rate are given. More magnetic cusps would enhance electrons’ drifting time, and a centralized electron distribution at anode surface would increase the collision probability between electrons and neutral gas. Nomenclature CFT = Cusped Field Thruster AP = Anode position ISP = Specific impulse MFS = Magnetic Field Strength MC = Magnetic Cusp HA = Hollow Anode FR = Flow Rate I......Introduction ultistage cusped field thruster is an emerging hall effect thruster recently. Have been developed by German’s HEMPT1, MIT’s DCFT2, Stanford University’s CCFT3 and many other institutes, this thruster concept mainly consists of four parts, which are magnet stages, cathode, discharging ceramic channel and anode with gas inlet. The magnet stages are located around the ceramic discharge channel, which are put in opposite poles for adjacent ones. These magnets can generate cusped magnetic field as shown in Figure.1. Electrons are released from cathode and moving towards anode direction powered by the electric field force. During the movement, electrons follow and do 1 Student, Department of Energy Science and Engineering, Harbin Institute of Technology, machengyu19930408@gmail.com 2 Lecturer, Department of Energy Science and Engineering, Harbin Institute of Technology, thruster@126.com 3 Professor, Department of Energy Science and Engineering, Harbin Institute of Technology, thruster@126.com 4 Student, Department of Energy Science and Engineering, Harbin Institute of Technology, 1437140573@qq.com 5 Student, Department of Energy Science and Engineering, Harbin Institute of Technology, 1151786040@qq.com 6 Student, Department of Energy Science and Engineering, Harbin Institute of Technology, 1634466984@qq.com M
The High Efficiency Multistage Plasma Thruster HEMPT based Ion Propulsion System for the SmallGEO Satellite
Thales Electron Devices GmbH TEDG has developed and is currently qualifying a novel type of ion propulsion system based on High Efficie ncy Multistage Plasma Thrusters HEMPTs. This so-called HEMPT Assembly will be integrated on OHB-System AG’s SmallGEO geo-stationary telecommunication platform to perform attitude and orbit control maneuvers for the Hispasat AG1 mission. The HEMPT Assembly consists of four HEMPT Modules and one Power Supply and Control Unit PSCU which supplies the HEMPT Modules with electric power and controls their operation. The so-called HEMPTIS program (HEMP Thruster In orbit verification on SmallGEO) initiated by German Space Agency DLR includes all associated component development, system engineering, testing and qualification activities, and the delivery of the r espective flight units. Currently, the HEMPT Assembly is undergoing the Critical Design Review CDR. All relevant activities to demonstrate the compliance of the HEMPT Assembly with the satellite requirements have been mostly accomplished and production of qualification and flight hardware has been started.