Institute for Space Weather Sciences

Title:   Erupting Solar Magnetic Flux Ropes and the Bz Challenge: Understanding Details of CME Propagation in the Interplanetary Media

Abstract:   Understanding the connection between magnetic topologies of a coronal mass ejection (CME) as observed closer to the Sun and in the interplanetary medium close to the Earth is vital for successful predictions of geomagnetic storms. Recent solar and magnetospheric data convincingly demonstrate that fast CMEs originating from near the solar disk center are the major cause of extreme space weather events. Moreover, topology and helicity of the ejected fields tend to be mainly preserved as the ejecta propagates and evolves in the interplanetary space. The interplanetary CME that is often observed near the Earth as a well organized helical structure called a magnetic cloud (MC) is the result of expansion of the original ejecta and its interaction with the heliospheric plasma and magnetic fields that may cause the ejecta to alter its shape, rotate and shed its magnetic flux. Therefore the probability of a strong geomagnetic storm to occur as well as its intensity depend on both initial properties of the erupted structure and the further interactions that the ejecta may be subjected to as it expands into the heliosphere. Detailed understanding of this interaction may shed light on the problems related to connecting solar surface phenomena to their interplanetary counterparts. In this talk I will briefly review current progress on the CMEs evolution in the heliosphere.