Magnetic field mapping of a field reversed configuration test article

Devices that form and accelerate field reversed configuration plasma may potentially be applied to spacecraft propulsion. Propulsion applications require heavy-gas plasma and the fundamental processes for heavy-gas field reversed configuration formation are still not well understood. Pre-ionization plasma properties are known to influence the success and final properties of field reversed configuration formation. In the following study the magnetic field of the pre-ionization stage of a heavy-gas field reversed configuration test article is presented. Initial results show discharge frequencies increase in the presence of plasma from 440 kHz in atmosphere discharges with no plasma to 472 kHz in 33 mTorr of air with plasma, both at an initial charge of 15 kV. Calibration of a three-axis magnetic field probe is completed using EMC Studio. Calibration values for the axial and azimuthal components of the probe are 4.66x10⁸ and 9.45x10⁷ G/V, respectfully. Magnetic field measurements at 15 and 20 kV are presented. The 15 and 20 kV discharges produce a peak current of 38 and 50 kA, respectfully. EMC simulations using these peak current values produce a maximum axial magnetic field of 632 and 819 G, respectfully. Measured axial magnetic field strengths of MPX at 15 and 20 kV using the B-dot probe yield 640 and 885 G, respectfully.