Work

Global Non-axisymmetric Hall Instabilities in a Rotating Plasma

Year: 2026

Type: article

Abstract: Non-axisymmetric, flow-driven instabilities in the incompressible Hall-MHD model are studied in a differentially rotating cylindrical plasma. It is found that, in the Hall-MHD regime, both whistler waves and ion-cyclotron waves can extract energy from the flow shear, resulting in two distinct branches of global instability. The non-axisymmetric whistler modes grow significantly faster than non-axisymmetric, ideal MHD modes. A discussion of the global whistler instability mechanism is presented in the large-ion-skin-depth, “electron-MHD” limit. When the magnetic field is azimuthal, a subset of the whistler modes having zero axial wave number are uncovered to be destabilized by the “corotation amplifier” mechanism. It is observed that the effect of the Hall term on the non-axisymmetric modes can be appreciable when d i is on the order of a few percent of the width of the cylindrical annulus. Distinct global modes emerge in the strong Hall-MHD regime at significantly stronger magnetic fields than those required for unstable global MHD modes, as the Hall effect weakens the stabilizing “field-line bending” by decoupling ion motion from the magnetic field. These global non-axisymmetric modes may play an important role in weakly ionized accretion disks.

Source: The Astrophysical Journal

DOI: 10.3847/1538-4357/ae5531

Authors: A.P. Sainterme, Fatima Ebrahimi

Institutions: Princeton University, Princeton Plasma Physics Laboratory

Language: English

Topic: Solar and Space Plasma Dynamics

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $4,499

Funder: National Science Foundation