Diamagnetism of a Supersonic Rotating Magnetized Plasma

Abstract

The Maryland Centrifugal Experiment (MCX) combines supersonic rotation with a magnetic mirror geometry to centrifugally confine a hydrogen plasma with the goal of investigating a magnetic confinement scheme applicable as a fusion reactor.

To demonstrate this axial confinement of plasma by centrifugal forces, an axial array of magnetic loops was installed, external to the vacuum vessel, to measure the axial and radial components of the magnetic field expelled by the plasma. The diamagnetic measurements show concentration of plasma pressure at locations of magnetic minima, as expected for centrifugal confinement.

Additionally, a visible light, multichord spectrometer was upgraded to ten chords allowing for the measurement of plasma rotation and temperature profiles with increased precision. Improved deconvolution techniques are investigated to further increase the precision of radial profiles calculated from multichord measurements.

A perturbative, ideal MHD equilibrium solution is then developed to relate the diamagnetic measurements to density, rotation, and temperature profiles of the plasma. This solution, along with density measurements by interferometery, is used to estimate rotation velocity and temperature of the plasma from magnetic data, and then is compared to spectroscopic measurements of rotation velocity and temperature radial profiles. Agreement between spectroscopic measurements and magnetic measurements via the MHD solution further demonstrate the presence of centrifugal confinement and its efficacy.