Schematic of how a localized instability can develop in an EMHD system with strong current density gradients. A localized electron flow perturbation in the direction of the current gradient displaces some of the background current due to the effect of electron inertia, resulting in a -field perturbation in the -plane. The same sheared background electron current then differentially rotates the perturbation and generates poloidal plasma currents, which reinforce the initial perturbation.
Scaling of the instability growth rate (a) with for and and (b) with for .
Profiles of the background current density (dashed line) and normalized eigenmode (solid line) from a quasilinear simulation with and . Full width at half maximum of the eigenmode is
Scaling of the aspect ratio of the instability eigenfunction vs for and .
Contour plots of (a) magnetic flux and (b) out-of-plane -field over the full computational domain from a simulation with after the nonlinear reconnection layer has fully developed.
Reconnection region contour plots of out-of-plane current density are shown in panels (a) and (c) and poloidal electron flow vorticity are shown in panels (b) and (d) from two simulation runs with , panels (a) and (b), and , panels (c) and (d), after the nonlinear reconnection layer has fully developed.
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