Self‐consistent magnetotail theory: General solution for the quiet tail with vanishing field‐aligned currents

Abstract

The three‐dimensional theory of the quiet magnetotail by Birn et al. (1977a) is revised and generalized. The general static solution is presented for the case of vanishing field‐aligned currents holding for quiet times with small bulk velocities and negligible pressure anisotropy. Since the knowledge of particle entry, transport, and loss and of the interaction of the magnetosphere with the solar wind is too small to determine the solution by appropriate initial and boundary conditions, the free functions of the general solution have been adjusted to the observational material inside the tail. It is shown that the quiet tail data can be fitted by a self‐consistent model without flux loss through the boundary (closed magnetosphere). Restrictions following from self‐consistency provide further (indirect) evidence for plasma sheet thickening towards the flanks. The effect of dipole tilt on the neutral sheet position and tail aberration can also be included in the model. It turns out that the curvature of the field lines in the x, y plane is connected with the occurence of field‐aligned currents.