Measurements of plasma isorotation on MCX

The Maryland Centrifugal Experiment (MCX) studies magnetically confined rotating plasma for fusion. Plasma is generated in a shaped mirror geometry magnetic field (B$_{end}$/B$_{mid} \quad \sim $ 8) by applying a static electric field perpendicular to the magnetic field. The dominant motion is the \textbf{E}$\times $\textbf{B} drift in a hydrogen plasma. Other drifts are smaller, typically because of the smallness of the gyroradius -- there are 50 --100 proton gyroradii across the field. MHD theory predicts that plasma angular velocity should be constant on a field line. Measurements on the isorotation of the plasma as obtained from spectroscopic measurements of the Doppler shift of impurity (C$^{+}_{, }$C$^{2+}$, O$^{+})$ and neutral lines are presented. The species angular velocity is measured simultaneously at the midplane and at 80 cm off-midplane. The dependency of the species angular velocity on the magnetic field -- for fixed mirror ratio -- as well as on the mirror ratio, applied voltage and static fill pressure is documented experimentally