Stabilization effect of magnetic shear on the diocotron instability

The diocotron instability in a magnetized non-neutral plasma is a close cousin of the Kelvin–Helmholtz instability. A sheared magnetic field brings about coupling between the diocotron modes and the Langmuir waves that propagate along the magnetic field. The motion of electrons parallel to the magnetic field cancels the electric charge produced by the diocotron modes, resulting in stabilization of the diocotron instability.