The use of magnetic fields to create high-speed plasma jets for spacecraft propulsion
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Open Access
Type
ThesisThesis type
Doctor of PhilosophyAuthor/s
Bathgate, Stephen NormanAbstract
The aim of the work reported in this thesis has been to explore arrangements of magnetic fields and electric currents to create novel plasma thrusters that are more efficient and less complex than existing designs. Two original devices are discussed, firstly a thruster that uses ...
See moreThe aim of the work reported in this thesis has been to explore arrangements of magnetic fields and electric currents to create novel plasma thrusters that are more efficient and less complex than existing designs. Two original devices are discussed, firstly a thruster that uses a magnetic nozzle in combination with a High Power Impulse Magnetron Sputtering source (HiPIMS) to produce a jet of copper plasma and secondly, a thruster that uses the phenomena of magnetic reconnection that occurs between opposing magnetic fields in a plasma to produce a plasma jet. While HiPIMS has been normally employed to create thin films, the use of a solenoidal magnetic field to accelerate and focus the ions produced by that source has not been previously investigated as a means of creating a thruster. The HiPIMS thruster has a specific impulse (Isp) of 1543s. Magnetic reconnection has been studied for decades by geophysicists and by astronomers. Despite that effort, so far there has been little interest in exploiting the phenomena as a means of producing high-speed plasmas in a thruster despite the evidence of jets in those environments. A thruster consisting of two slit coaxial tubes of copper was constructed. Evidence for the occurrence of magnetic connection was fourfold. (1) A significant electron current that coincided with the rise of the magnetic field that was followed by a large ion current. (2) Ion currents were found to increase as the plasma became less collisional. (3) Ions with energies greater than 130 eV corresponding to a speed of 2.50 x 104 m/s and an Isp of 2550s were detected. (4) The ratio between the estimated speed of ions flowing into the diffusion layer (350m/s) and the measured speed of the out-flowing ions (2.50 x 104 m/s) was approximately 68. The physics indicates that such a thruster could have a basic energy efficiency of 50%.
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See moreThe aim of the work reported in this thesis has been to explore arrangements of magnetic fields and electric currents to create novel plasma thrusters that are more efficient and less complex than existing designs. Two original devices are discussed, firstly a thruster that uses a magnetic nozzle in combination with a High Power Impulse Magnetron Sputtering source (HiPIMS) to produce a jet of copper plasma and secondly, a thruster that uses the phenomena of magnetic reconnection that occurs between opposing magnetic fields in a plasma to produce a plasma jet. While HiPIMS has been normally employed to create thin films, the use of a solenoidal magnetic field to accelerate and focus the ions produced by that source has not been previously investigated as a means of creating a thruster. The HiPIMS thruster has a specific impulse (Isp) of 1543s. Magnetic reconnection has been studied for decades by geophysicists and by astronomers. Despite that effort, so far there has been little interest in exploiting the phenomena as a means of producing high-speed plasmas in a thruster despite the evidence of jets in those environments. A thruster consisting of two slit coaxial tubes of copper was constructed. Evidence for the occurrence of magnetic connection was fourfold. (1) A significant electron current that coincided with the rise of the magnetic field that was followed by a large ion current. (2) Ion currents were found to increase as the plasma became less collisional. (3) Ions with energies greater than 130 eV corresponding to a speed of 2.50 x 104 m/s and an Isp of 2550s were detected. (4) The ratio between the estimated speed of ions flowing into the diffusion layer (350m/s) and the measured speed of the out-flowing ions (2.50 x 104 m/s) was approximately 68. The physics indicates that such a thruster could have a basic energy efficiency of 50%.
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Date
2017-02-28Faculty/School
Faculty of Science, School of PhysicsAwarding institution
The University of SydneyShare