Design and construction of the magnetic perturbation magnets of the space plasma environment research facility for simulating the geomagnetic storm on the ground

Abstract

Geomagnetic storm in the magnetosphere of the earth is significant in understanding the basic space plasma processes such as wave-particle interaction and predicting the space weather related to the human activity. Due to defects involved in the space observation and theoretical modeling, it is urgent to investigate it in the laboratory based on a simulation facility. To that end, two circular magnetic perturbation magnets are proposed in the SPERF (Space Plasma Environment Research Facility) to generate the magnetic disturbances with different characteristic times for studying the response of the inner magnetosphere to the geomagnetic storm. The paper focuses on the engineering design and construction of the magnets. The scaling relation for geomagnetic storm simulation is presented, serving as the design requirement of the magnets. Then, starting with giving the designed parameters of the magnets satisfying the requirement and analyzing the crucial issues facing their engineering design, the design results, manufacturing procedure, and test results are presented, with emphasize on the measures to improve the insulation, vacuum degree, and plasma quality. Then, mechanical analyses are done to evaluate the strength of the supporting mechanism of the magnets under the magnetic force and torque caused by the possible deviation from the concentricity with the dipole magnet. Afterwards, a connection scheme is designed to make the coaxial cables connecting to the magnet's leads go through the vacuum vessel considering the constraints of the magnetic-force impact, thermal burden, and motion requirement. One of the magnetic perturbation magnets has been installed in the SPERF, and is now being tested combined with the pulsed power supply.