Exposure to the energetic particles associated with solar energetic particle events (SEP's) and galactic cosmic rays (GCR's) are known radiation hazards for human exploration. Material shielding and superconducting solutions add substantial mass to spacecraft and provide shielding over very limited areas. This paper will present the shielding capabilities of Plasma Magnetic Shield (PMS) which makes use of ambient low density plasma ejected from the spacecraft that supports the large scale currents required to provide sufficient magnetic flux to deflect SEPs and GCRs at large distances. The plasma currents are produced and sustained by a Rotating Magnetic Field (RMF) produced by a pair of polyphase antennas. The antennas consist of simple hoops on the order of 100 m scale or more, and are driven by a tuned oscillator circuit driven by solid state devices at kHz frequencies. The associated magnetic field from the driven plasma currents make up what is referred to as a plasma magnet. The size of the plasma magnet can be made such that it offers protection of the spacecraft but also protection of astronauts involved in EVAs and/or lunar surface exploration. Since the energetic particles do not interact with any nuclei, issues of exposure to hazardous secondaries are also minimized. The proposed system has been produced experimentally on a smaller scale and modeled numerically with all the results strongly indicating that the proposed active shielding can indeed be achieved. The challenge will be in determining accurate scaling laws to large scale within the confines of a small terrestrial vacuum chamber. Results to date, and the expected operating parameters of the PMS will be presented. Future work would seek to quantify the power and mass requirements of an optimized system from a large chamber experiment with extrapolation from validated computer simulations to true space conditions.
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