Dipolarization fronts in the magnetotail plasma sheet

A. Runov, V. Angelopoulos, M. Sitnov, V. A. Sergeev, R. Nakamura, Y. Nishimura, H. U. Frey, J. P. McFadden, D. Larson, J. Bonnell, K. H. Glassmeier, U. Auster, M. Connors, C. T. Russell, H. J. Singer

Research output: Contribution to journalJournal Articlepeer-review

70 Citations (Scopus)


We present a THEMIS study of a dipolarization front associated with a bursty bulk flow (BBF) that was observed in the central plasma sheet sequentially at X=-20.1, -16.7, and -11.0RE. Simultaneously, the THEMIS ground network observed the formation of a northsouth auroral form and intensification of westward auroral zone currents. Timing of the signatures in space suggests earthward propagation of the front at a velocity of 300 km/s. Spatial profiles of current and electron density on the front reveal a spatial scale of 500 km, comparable to an ion inertial length and an ion thermal gyroradius. This kinetic-scale structure traveled a macroscale distance of 10RE in about 4 min without loss of coherence. The dipolarization front, therefore, is an example of space plasma cross-scale coupling. THEMIS observations at different geocentric distances are similar to recent particle-in-cell simulations demonstrating the appearance of dipolarization fronts on the leading edge of plasma fast flows in the vicinity of a reconnection site. Dipolarization fronts, therefore, may be interpreted as remote signatures of transient reconnection.

Original languageEnglish
Pages (from-to)517-525
Number of pages9
JournalPlanetary and Space Science
Issue number7
Publication statusPublished - May 2011


  • Planetary magnetosphere
  • Plasma sheet
  • Reconnection


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