Accelerated thinning of the near-Earth plasma sheet caused by a bubble-blob pair
In the late stage of a substorm growth phase, the magnetic field in the near‐Earth region is highly stretched. We assume that such conditions can lead to violation of the frozen‐in‐flux condition, allowing transfer of plasma from one flux tube to another and creating a plasma blob tailward of a plas...
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Veröffentlicht in: | Geophysical research letters 2011-01, Vol.38 (1), p.np-n/a |
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Sprache: | eng |
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Zusammenfassung: | In the late stage of a substorm growth phase, the magnetic field in the near‐Earth region is highly stretched. We assume that such conditions can lead to violation of the frozen‐in‐flux condition, allowing transfer of plasma from one flux tube to another and creating a plasma blob tailward of a plasma bubble. In this letter we present results of a simulation where we artificially impose a bubble‐blob pair by introducing a disturbance in PV5/3 in the near‐Earth plasma sheet. In the subsequent evolution, as calculated by the equilibrium version of the Rice Convection Model (RCM‐E), the bubble surges earthward and the blob moves tailward, while the magnetic field between them weakens and the localized cross‐tail current density increases. We speculate that, at substorm onset, there could be a positive feedback in which the breakdown of the frozen‐in condition would increasingly make the current sheet thinner until magnetic reconnection occurs. |
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ISSN: | 0094-8276 1944-8007 |
DOI: | 10.1029/2010GL045993 |