Origins of Rolling, Twisting and Non-radial Propagation of Eruptive Solar Events
Abstract
We demonstrate that major asymmetries in erupting filaments and CMEs are not only related to each other but that major twists and non-radial motions typically are related to the larger, more global environment around eruptive events. This overarching result grew out of a number of earlier studies that we now encapsulate within the bigger picture. If a filament erupts non-radially, as frequently happens, the top of its spine first bends to one side and evolves into a sideways rolling motion. As shown by 304 Angstrom observations from SOHO and STEREO and earlier H alpha Doppler observations, the rolling motion propagates down the legs of erupting filaments resulting in the large scale twists commonly observed in them. The initial rolling initiates twist of opposite chirality in the two legs. In addition to the observed absence of twist in the pre-eruptive state, further evidence that the energy creating the twist comes from above was found in Doppler shifts; the rotational motions in the legs of erupting filaments are not only opposite in sign to each other but the twists in both legs are opposite in sign to that required if the observed sense of twist were generated at the feet or in the legs of the erupting filament. We next demonstrate that the combined ascent and initial bending is non-radial in the same general direction as for the surrounding CME. However, the non-radial motion of the filament is greater than that of the CME. In considering the global environment around CMEs, as can be approximated by the Potential Field Source Surface (PFSS) Model, we found that both erupting filaments and their surrounding CMEs are non-radial only in the direction away from a nearby coronal hole and toward local and global null points. Due to the presence of the coronal hole, the global forces on the CME are asymmetric. The CME propagates non-radially in the direction of least resistance and that is always away from the coronal hole as we demonstrate by comparing low latitude and high latitude examples. Through modeling and comparison with observed events, we anticipate that major twists and non-radial motions in erupting prominences and CMEs will become predictable to the extent that their environments are well-defined and measurable.
- Publication:
-
SDO-3: Solar Dynamics and Magnetism from the Interior to the Atmosphere
- Pub Date:
- October 2011
- Bibcode:
- 2011sdmi.confE.105M
- Keywords:
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- SDO;
- SDO-3;
- SDO 3;
- SDO Workshop;
- LWS/SDO-3/SOHO-26/GONG-2011 Workshop;
- Solar Dynamic Observatory