Preliminary Results on an Annular Field Reversed Configuration Translation Experiment (Preprint)

Authors: Carrie S Hill; ENGINEERING RESEARCH AND CONSULTING INC (ERC INC) EDWARDS AFB CA

Abstract:

Annular field reversed configuration (AFRC) devices form annular plasma toroids between a pair of concentric cylindrical coils. The plasma toroid (plasmoid) remains detached from the external magnetic field so that it can be ejected from the coils, making AFRCs potential pulsed inductive plasma accelerators. Though numerous formation studies on AFRCs are available, no successful translation studies have been published. Michigan Technological University, in conjunction with the Air Force Research Laboratory, is investigating the translation of AFRCs as pulsed inductive plasma accelerators. The experiment, the XOCOT-T3, uses a 9 kHz RLC circuit with multi-turn copper coils to form and accelerate the plasmoid. Magnetic b-dot probes along the device record the magnetic field on the inner and outer radii of the annulus. Rogowski current monitors measure the current through the coils and are used to estimate the energy deposition into the plasma. Images from a high speed camera provide information about gross plasmoid behavior. XOCOT-T3 was tested from 100 J to 500 J with an Argon background gas fill from 1 mTorr to 20 mTorr. Details on formation at 500 J and 4 mTorr show that while a field reversed configuration is created, the plasmoid does not translate. Instead, the plasmoid appears to be limited in lifetime to 10 μs, extinguishing before it has a chance to translate.

Limitations:

APPROVED FOR PUBLIC RELEASE