Signs of magnetic helicity in interplanetary coronal mass ejections and associated prominences: Case study

Abstract

We study the distribution of magnetic helicity in interplanetary coronal mass ejections (CMEs) separated into magnetic clouds and remnants of the prominence structures for three cases with identified remnants of prominences. The magnetic configurations of magnetic clouds and prominence remnants can satisfactorily be described by the flux rope approximation. It is shown that the magnetic helicities in both parts of the CMEs have the same sign. This sign is consistent with the dominance of CMEs with negative helicity in the northern hemisphere and positive in the southern hemisphere. The results are discussed in the context of different models of CME eruption at the Sun.