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Uncovering Erosion Effects on the Twist Distribution in Cross-section of Magnetic Clouds
Sanchita Pal - University of Helsinki, Finland; Emilia Kilpua - University of Helsinki, Finland; Jens Pomoell - University of Helsinki, Finland; Simon Good - University of Helsinki, Finland; Daniel Price - University of Helsinki, Finland
Magnetic clouds (MCs) are large-scale interplanetary twisted magnetic flux ropes that originate from the Sun. Their interaction with an ambient interplanetary magnetic field may result in erosion. The twist of MCs' magnetic field lines yields information about their formation and geoeffectiveness. We investigate the twist distribution in the cross-section of two MCs, which travel across spacecraft with their cores and leave behind post-eruption arcades as a coronal signature at their solar sources. We observe a monotonous decrease in one of the two MCs' twist profile from the axis to the periphery. In contrast, the twist in the other one initially decreases from its maximum value near the axis, becomes roughly uniform in the central half part, and gradually increases towards the edge. We suggest that a moderate increase in twist values towards the MC boundaries may result from helical field lines that wrap around the flux ropes formed due to low-coronal magnetic reconnection between pre-existing flux ropes and overlying field lines. We compare MCs' magnetic properties within the Sun-Earth domain and find that the MC with a monotonically decreasing twist profile is eroded more than the other, and the erosion peels off the MC's outer layer comprising twisted field lines.
16 July 2020
Abstract submission opens:
16 July 2020
European Space Weather Medals:
6 September 2020
25 September 2020
Registration deadline: [extended]
10 October 2020
Abstract submission deadline:
4 September 2020