How typical are atypical current sheets?

Y. Asano , R. Nakamura , W. Baumjohann , A. Runov , Z. Vörös , M. Volwerk , T. L. Zhang , A. Balogh , B. Klecker , H. Rème (1)

1 CESR - Centre d'étude spatiale des rayonnements

Using multi-satellite Cluster magnetic field data, we statistically examined how often an atypical, i.e., non-Harris type, current sheet is formed. We found that a cross-tail current sheet with an off-equatorial current density maximum, indicating bifurcation, is frequently formed in thin current sheets with a half thickness of $1500 km. The occurrence of off-equatorial current density maxima is correlated with the occurrence of fast plasma flows, namely if fast plasma flows occur nearby, one is more likely to observe off-equatorial current density maxima. We also found that many of the center-peaked current sheets exhibit a feature different from a normal Harris sheet: namely a very intense current concentrated near the equatorial plane, embedded in a broader current sheet with lower current density.

Domaines: Astrophysique [astro-ph]; Cosmologie et astrophysique extra-galactique [astro-ph.CO]

Y. Asano, R. Nakamura, W. Baumjohann, A. Runov, Z. Vörös, et al.. How typical are atypical current sheets?. Geophysical Research Letters, 2005, 32, pp.issue 3. ⟨10.1029/2004GL021834⟩. ⟨hal-00013048⟩