Derivation of currents and diamagnetic effects from global plasma pressure distributions obtained by IMAGE/HENA Original Research Article

The global ion distributions extracted from ENA images measured by IMAGE/HENA can be used to calculate the plasma pressure. In principle, knowing the plasma-pressure distribution and the magnetic field, one can also calculate the three-dimensional current system that is driven by the pressure gradient. The currents depend on the pressure gradient and the magnetic-field strength. Assuming current continuity (∇·J=0), we can use Euler potentials for J itself to calculate the current distribution. The method is applied to some pressure distributions measured by IMAGE/HENA and the resulting field-aligned currents (FACs) are compared to the global FAC maps derived from irridium magnetometer data.