Development of plasma sources for Dipole Research EXperiment (DREX)

Dipole Research EXperiment (DREX) is a new terrella device as part of the Space Plasma Environment Research Facility (SPERF) for laboratory studies of space physics relevant to the inner magnetospheric plasmas.Adequate plasma sources are very important for DREX to achieve its scientific goals.According to different research requirements,there are two density regimes for DREX.The low density regime will be achieved by an electron cyclotron resonance (ECR) system for the ‘whistler/chorus' wave investigation,while the high density regime will be achieved by biased cold cathode discharge for the desired ‘Alfvén’ wave study.The parameters of ‘whistler/chorus’ waves and ‘Alfvén’ waves are determined by the scaling law between space and laboratory plasmas in the current device.In this paper,the initial design of these two plasma sources for DREX is described.Focus is placed on the chosen frequency and operation mode of the ECR system which will produce relatively low density ‘artificial radiation belt’ plasmas and the seed electrons,followed by the design of biased cold cathode discharge to generate plasma with high density.Dipole Research EXperiment (DREX) is a new terrella device as part of the Space Plasma Environment Research Facility (SPERF) for laboratory studies of space physics relevant to the inner magnetospheric plasmas.Adequate plasma sources are very important for DREX to achieve its scientific goals.According to different research requirements,there are two density regimes for DREX.The low density regime will be achieved by an electron cyclotron resonance (ECR) system for the ‘whistler/chorus' wave investigation,while the high density regime will be achieved by biased cold cathode discharge for the desired ‘Alfvén’ wave study.The parameters of ‘whistler/chorus’ waves and ‘Alfvén’ waves are determined by the scaling law between space and laboratory plasmas in the current device.In this paper,the initial design of these two plasma sources for DREX is described.Focus is placed on the chosen frequency and operation mode of the ECR system which will produce relatively low density ‘artificial radiation belt’ plasmas and the seed electrons,followed by the design of biased cold cathode discharge to generate plasma with high density.National Natural Science Foundation of China; China Postdoctoral Science Foundation; HIT.NSRIF under Grant No.2017008515-201