Simulation of auroral current sheet equilibria and associated V‐shaped potential structures

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Abstract
Results from numerical simulations of auroral current sheet equilibria and associated V‐shaped potential structures are presented. It is shown that with allowance for both hot magnetospheric ion and cold ionospheric ion populations, the perpendicular potential drop, Φm, associated with a non‐neutral auroral current sheet is critically controlled by the temperature of the ‘heated’ ionospheric ions. The heating is caused by the wave turbulence excited by the auroral current sheet. In the presence of heated ionospheric ions, a relatively large variation in the temperature of the hot magnetospheric ion population causes a very small variation in the potential drop Φm. The perpendicular potential drop acts to produce a V‐shaped double layer with multiple potential steps parallel to the magnetic field when a zero potential boundary condition is imposed at the ionospheric boundary. Outside the V‐shaped potential structure, ionospheric return currents develop self‐consistently.