Electromagnetic effect on the toroidal electron temperature gradient mode

The electromagnetic effect on the toroidal electron temperature gradient mode is investigated using local kinetic and fluid theories. It is found that the electromagnetic effect on the toroidal mode differs from that for the slab mode. For the slab mode, the electromagnetic effect gives a strong stabilization, while for the toroidal mode there is a destabilization. In particular, the modes with perpendicular wavelength comparable to the electron skin depth are destabilized by the finite electron inertia. It is shown that this contrasting result for the toroidal mode occurs mainly because the stabilizing effect of the parallel transit drift is significantly reduced by the finite electromagnetic term.