• Media type: E-Article
  • Title: Tail Reconnection Triggering Substorm Onset
  • Contributor: Angelopoulos, Vassilis; McFadden, James P.; Larson, Davin; Carlson, Charles W.; Mende, Stephen B.; Frey, Harald; Phan, Tai; Sibeck, David G.; Glassmeier, Karl-Heinz; Auster, Uli; Donovan, Eric; Mann, Ian R.; Rae, I. Jonathan; Russell, Christopher T.; Runov, Andrei; Zhou, Xu-Zhi; Kepko, Larry
  • Source: Science ; 321 ( 2008 ) S. 931-935
  • Published: American Association for the Advancement of Science, 2008
  • Language: English
  • DOI: 10.1126/science.1160495
  • ISSN: 0036-8075; 1095-9203
  • Keywords: Research Article
  • Abstract: <p>Magnetospheric substorms explosively release solar wind energy previously stored in Earth's magnetotail, encompassing the entire magnetosphere and producing spectacular auroral displays. It has been unclear whether a substorm is triggered by a disruption of the electrical current flowing across the near-Earth magnetotail, at ∼10 $R_{\text{E}}$ ($R_{\text{E}}$: Earth radius, or 6374 kilometers), or by the process of magnetic reconnection typically seen farther out in the magnetotail, at ∼20 to 30 $R_{\text{E}}$. We report on simultaneous measurements in the magnetotail at multiple distances, at the time of substorm onset. Reconnection was observed at 20 $R_{\text{E}}$, at least 1.5 minutes before auroral intensification, at least 2 minutes before substorm expansion, and about 3 minutes before near-Earth current disruption. These results demonstrate that substorms are likely initiated by tail reconnection.</p>
  • Description: <p>Magnetospheric substorms explosively release solar wind energy previously stored in Earth's magnetotail, encompassing the entire magnetosphere and producing spectacular auroral displays. It has been unclear whether a substorm is triggered by a disruption of the electrical current flowing across the near-Earth magnetotail, at ∼10 $R_{\text{E}}$ ($R_{\text{E}}$: Earth radius, or 6374 kilometers), or by the process of magnetic reconnection typically seen farther out in the magnetotail, at ∼20 to 30 $R_{\text{E}}$. We report on simultaneous measurements in the magnetotail at multiple distances, at the time of substorm onset. Reconnection was observed at 20 $R_{\text{E}}$, at least 1.5 minutes before auroral intensification, at least 2 minutes before substorm expansion, and about 3 minutes before near-Earth current disruption. These results demonstrate that substorms are likely initiated by tail reconnection.</p>
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