Forming tori: Implications and possible origins of a "tethered spheromak" topology for magnetic clouds
Abstract
We present a "tethered spheromak" model for magnetic clouds. The proposed topology differs from previous magnetic cloud models invoking spheromaks in that large portions of the field remain connected to the sun. This magnetic configuration may explain observed departures from the standard magnetic cloud model of a cylindrically-symmetric magnetic flux rope, such as magnetic fields which rotate more than 180 degrees. It is also topologically complex enough to include intermingled detached, doubly attached, and apparently open fields in a manner consistent with observations of sporadic heat flux dropouts within otherwise bidirectional or unidirectional streaming electrons. We use a numerical simulation to demonstrate how, for solar eruptions where the kink instability drives significant rotation of an erupting flux rope, such a tethered spheromak may form during that rope's partial ejection. It does so because writhing motions and reconnections create twist about two distinct axes of rotation: the first associated with the rotated portion of the original rope axis, and the second formed in situ via reconnections between the erupting rope and surrounding coronal arcade fields.
- Publication:
-
AGU Spring Meeting Abstracts
- Pub Date:
- May 2008
- Bibcode:
- 2008AGUSMSH31C..06G
- Keywords:
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- 7513 Coronal mass ejections (2101);
- 7524 Magnetic fields;
- 7526 Magnetic reconnection (2723;
- 7835);
- 7954 Magnetic storms (2788)