Kinetic aspects of the Jovian current sheet

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Abstract
In this work, self‐consistent two‐dimensional particle simulations are used to examine the structure and dynamics of the current sheet in the middle and outer regions of the Jovian magnetotail. A plasma source, representing plasma transported outward from Io, is injected into the simulation system of a corotating magnetodisc configuration that is initially at hydromagnetic equilibrium. Simulations show that the corotating magnetodisc equilibrium evolves into a new configuration in which plasma outflow is present and the ion and electron outflows are different. The initial hydromagnetic equilibrium also develops a cross‐sheet charge separation, an electrostatic potential, and a polarization electric field normal to the sheet. We observe a relatively stable current sheet and a steady, moderate outflow inside the Alfvén radius. Outside the Alfvén radius, a corotation lag spiral magnetic field, radial outward currents carried by the ions, and electron diamagnetic drifts in the polarization field are found. In this region the centrifugally slung plasma may break the magnetic field topology through driven reconnection. During strong reconnection the magnetic field configuration in the plasmoid region is observed to change from corotation lag to corotation lead; the magnetodisc plasma escapes into a super‐Alfvénic outflow, and fast‐shock‐like layers form. Ion heating and non‐Maxwellian velocity distributions are found in these regions.