Electron-inertia effects on the transverse gravitational instability

This paper studies the non-ideal electron inertial effects on the gravitational instability of a medium permeated by a magnetic field both in the presence and absence of rotation. It is seen that the inertial effects become important when considering the transverse perturbations as, in this case, the compressional wave, modified by the electron-inertial terms (inertial compressional wave -ICW), can modify the Jeans gravitational criterion. A band of wavenumber is introduced around the Jeans wavenumber for which the ICW is found to have a destabilizing effect. The width of the band depends on the parameter β, the ratio of sound to Alfven speed, and the electron inertial length δ. In the case of rotation it is seen that when the perturbations are transverse to the direction of the magnetic field and the rotational axis the system is stable for all wave numbers for rotational frequencies greater than a critical value. Otherwise, the unstable range of wavenumbers introduced by the inertial effects is also modified by the Coriolis force. (author)