Magnetopause from pressure balance

The shape of the magnetopause and the field due to magnetopause currents ar e calculated from the requirement that the pressure in the magnetosheath be balanced by magnetic pressure inside the magnetosphere. The field due to m agnetopause currents is calculated to be consistent with the iteratively ad justed magnetopause shape. The field due to current systems inside the magn etosphere is taken from the T96 model [Tsyganenko, 1996], which carries inf ormation from similar to 47,000 magnetic field observations. Many different magnetospheric configurations were found for a variety of conditions. Chan ges in the shape of the magnetopause with varying dipole tilt angle stood o ut. The magnetotail and the nose (the point closest to the Sun) were found to shift vertically, in opposite directions, for nonzero dipole tilt. The v ertical offset of the nose from the Earth-Sun line varied linearly with dip ole tilt angle, reaching similar to 3 R-E for maximal tilt and having a wea k dependence on solar wind dynamic pressure. The formation of a secondary s tagnation point just above the sunward cusp was indicated for absolute dipo le tilts in excess of 15 degrees. The magnitude of the field strength at it s local maximum just behind the cusp was determined as a function of dipole tilt angle and the subsolar field strength. Calculated magnetopause shapes and observed magnetopause crossings were found to be consistent when the t ilt angle was taken into account. Variations in the latitude of the magneti c cusps with dynamic pressure, interplanetary magnetic field B-z, and dipol e tilt were reasonably consistent with observed variations in the latitude of the particle cusp.