INTERPLANETARY MAGNETIC CLOUDS - TOPOLOGY AND DRIVING MECHANISM

A model is developed to study the origin and propagation of magnetic clouds. Starting with an equilibrium current loop embedded in an ambient plasma consistent with the solar corona, magnetic energy is injected by increasing the loop current. This causes the loop to rise, propelling plasma and magnetic field away from the Sun. Using a simple model of the interplanetary medium, the subsequent dynamics of the loop is calculated to 1 AU and beyond. The macroscopic properties of the resulting structures at 1 AU closely resemble those of observed magnetic clouds. Thermal effects indicate that clouds remain magnetically connected to the Sun in order to yield observed temperatures near 1 AU.