Centrifugal instability in a weakly magnetized rotating plasma column

A two-fluid model is developed to study the stability of weakly magnetized rotating plasma columns. Previous works have shown that rotating plasma columns are prone to centrifugal flute modes. Most of these models are based on the low-frequency assumption which is valid when the instability frequency and the plasma azimuthal frequency are small compared with the ion cyclotron frequency. This assumption is challenged in many laboratory plasma devices, including weakly magnetized plasma columns. A radially global dispersion relation relaxing the low-frequency approximation and applicable in these devices is derived. The validity domain of the low-frequency approximation is discussed. In addition, the impact of the radial boundary on the linear stability is investigated and comparison with results obtained in the radially local approximation are performed.

Automated summary

A two-fluid model is used to investigate the stability of weakly magnetized rotating plasma columns, which are prone to centrifugal flute modes. Previous models based on low-frequency assumption are not applicable in laboratory plasma devices, including weakly magnetized plasma columns. Thus, a radially global dispersion relation is derived to relax the low-frequency approximation and investigate linear stability in these devices. The impact of the radial boundary on stability is also examined and compared with results obtained in the radially local approximation.