Centrifugal instability in the regime of fast rotation

Centrifugal instability, which stems from a difference between the azimuthal angular drift velocity of ions and electrons, is studied in the limit of fast rotation for which ions can rotate up to twice as fast as electrons. As the angular velocity approaches the so-called Brillouin limit, the growth rate for the centrifugal instability in a collisionless solid-body rotating plasma increases markedly and is proportional to the azimuthal mode number. For large wavenumbers, electron inertia effects set in and lead to a cut-off. Interestingly, conditions for the onset of this instability appear to overlap with the operating conditions envisioned for plasma mass separation devices.