Three-dimensional artificial neural network model of the dayside magnetopause

Artificial neural networks (ANN) from the package NeuroShell 2 are applied to the modeling of the dayside magnetopause. The model data set is based on magnetopause crossings and on the corresponding hour-averaged measurements of the solar wind plasma and the interplanetary magnetic field. The ANN model represents the three-dimensional shape and size of the dayside magnetopause as a function of the solar wind dynamic pressure and the B_z and B_y components of the interplanetary magnetic field. The model describes the dynamics of the magnetic cusp and global asymmetry of the dayside magnetopause under a wide range of external conditions. Small variations in the size of the magnetopause as a function of the absolute value of B_y are presented quantitatively in the form of an analytic expression. The ANN model shows three regimes of magnetopause dynamics that are controlled by the B_z component: a pressure balance regime (B_z>0 nT), a reconnection regime (0>B_z>-10 nT), and a regime of reconnection saturation (B_z<-10 nT). Also, three different regimes of magnetopause dynamics at the subsolar point are described by a modified pressure balance equation obtained from the ANN model.