MAGNETIC STRUCTURE OF CMES

Abstract. We present several models of the magnetic structure of solar coronal mass ejections (CMEs). First, we model CMEs as expanding force-free magnetic structures. While keeping the internal magnetic field structure of the stationary solutions, expansion leads to complicated internal velocities and rotation, while the field structures remain force-free. Second, expansion of a CME can drive resistive dissipation within the CME changing the ionization states of different ions. We fit in situ measurements of ion charge states to the resistive spheromak solutions. Finally, we consider magnetic field structures of fully confined stable magnetic clouds containing both toroidal and poloidal magnetic fields and having no surface current sheets. Expansion of such clouds may lead to sudden onset of reconnection events. 1. Force-free expansing CMEs Expansion of magnetic clouds is one of the basic problems in space physics and geophysics, related to propagation of solar disturbances, the coronal mass ejections (CMEs) through interplanetary medium (Forbes et al., 2006). As the space craft passes through the cloud, the magnetic field strength is higher than average, the density is lower, the magnetic pressure inside the cloud greatly exceeds the ion thermal pressure and the magnetic field direction changes through the cloud (e.g. Burlaga et al., 1982). Spheromaks are stationary force-free configurations of plasma satisfy-ing the condition J = αB with spatially constant α. They are solutions o