A new high-rotation (HR) mode of operation is reported for magnetized rotating plasmas. Plasma is produced by an externally applied radial electric field in the Maryland centrifugal experiment, a mirror magnetic field plasma rotating azimuthally. The HR mode is achieved by optimizing over the discharge current. Previously reported stationary or steadily declining plasma voltages are now replaced by time-increasing voltages in the HR mode, with maximum voltages significantly higher than those previously recorded. Sonic Mach numbers are close to the theoretical values required for centrifugal confinement and for suppressing large scale magnetohydrodynamic (MHD) instabilities. Plasma momentum confinement time is much longer than the MHD instability time scale and longer than in ordinary mode operation. The mode is sustained over several confinement times.