The location and shape of the magnetopause

In this paper, we provide a comprehensive review on the development of magnetopause location research over the past four decades, starting from John R. Spreiter's early fundamental work on the shape of the magnetopause as a function of dipole tilt angle. Several 2-D empirical magnetopause location models were developed later using in situ magnetopause crossings mainly from low-latitude satellites under an assumption of axisymmetry of the magnetopause shape to the Sun-Earth line. As more magnetopause crossings at higher latitudes and in the distant tail were obtained from space missions, interest in the 3-D shape of the magnetopause, including the high-latitude magnetopause and magnetotail cross section, is growing. Increasing computer power has made 3-D numerical modeling and artificial neutral network technique more efficient to derive the global magnetopause shape and its dependence on solar wind conditions. Presently, the magnetopause location has been modeled as functions of the solar wind dynamic pressure and interplanetary magnetic field (IMF) B_z. Some evidence has shown that magnetopause erosion saturates when the southward IMF is extremely strong.