Anisotropic magnetotail equilibrium and convection

This paper reports on self‐consistent two‐dimensional equilibria with anisotropic plasma pressure for the Earth's magnetotail. These configurations are obtained by numerically solving the generalized Grad‐Shafranov equation, describing anisotropic plasmas with p∥ ≠ p⟂, including the Earth's dipolar field. Consistency between these new equilibria and the assumption of steady‐state, sunward convection, described by the double‐adiabatic laws, is examined. As for the case of isotropic pressure [Erickson and Wolf, 1980], there exists a discrepancy between typical quiet‐time magnetic field models and the assumption of steady‐state double‐adiabatic lossless plasma sheet convection. However, unlike that case, this inconsistency cannot be removed by the presence of a weak equatorial normal magnetic field strength in the near tail region: magnetic field configurations of this type produce unreasonably large pressure anisotropies, p∥ > p⟂, in the plasma sheet.