| The Plasmoid Thruster Experiment (PTX) is a test-bed for studying pulsed inductively-coupled plasma acceleration. The PTX discharges a current through a conical theta-pinch coil to form and accelerate plasma. Recently, the experiment was moved into a new vacuum chamber, and a three-axis magnetic field probe array was employed to map the magnetic field topology and evolution. Using nitrogen in the new experimental setup, results showed multiple vortices formed in succession, though they did not appear to accelerate beyond the mouth of the coil. Magnetic pressure was greatest between the coil and the plasmoids and along the axis, suggesting that the gas pressure is highest in between these two regions. Limited regions of the flowfield in the vicinity of the plasmoid gave expected, order of magnitude estimates of the density, and the technique employed can be used as a consistency check on more comprehensive diagnostics in the future. |
