Parametric study of loop‐like magnetic cloud propagation

Propagation and evolution of loop‐like magnetic clouds in the ambient solar wind flow are studied self‐consistently using ideal MHD equations in the 2½ dimensional approximation. Magnetic clouds, as ideal force‐free objects (cylinders lying in the ecliptic plane), are ejected near the Sun and followed beyond the Earth's orbit. We investigate the influence of various initial parameters, like the injection velocity or different steady states of the solar wind, on their propagation and evolution. Simulation results are compared with an analytical theory of magnetic cloud evolution (expansion) published by Osherovich et al. [1993a, b]; good agreement is found, although no need to use a polytropic index less than 1 (as in the analytical approach) is required.