Evolution of dipolarization in the near-Earth current sheet induced by Earthward rapid flux transport

By R. Nakamura, A. Retinò, Wolfgang Baumjohann, M. Volwerk, N. Erkaev, Berndt Klecker, E. Lucek, I. Dandouras, Mats André, Y. Khotyaintsev. 2009

148 citations recorded by the source corpus.

Abstract. We report on the evolution of dipolarization and associated disturbances of the near-Earth current sheet during a substorm on 27 October 2007, based upon Cluster multi-point, multi-scale observations of the night-side plasma sheet at X~−10 R E . Three dipolarization events were observed accompanied by activations on ground magnetograms at 09:07, 09:14, and 09:22 UT. We found that all these events consist of two types of dipolarization signatures: (1) Earthward moving dipolarization pulse, which is accompanied by enhanced rapid Earthward flux transport and is followed by current sheet disturbances with decrease in B Z and enhanced local current density, and subsequent (2) increase in B Z toward a stable level, which is more prominent at Earthward side and evolving tailward. During the 09:07 event, when Cluster was located in a thin current sheet, the dipolarization and fast Earthward flows were also accompanied by further thinning of the current sheet down to a half-thickness of about 1000 km and oscillation in a kink-like mode with a period of ~15 s and propagating duskward. Probable cause of this "flapping current sheet" is shown to be the Earthward high-speed flow. The oscillation ceased as the flow decreased and the field configuration became more dipolar. The later rapid flux transport events at 09:14 and 09:22 UT took place when the field configuration was initially more dipolar and were also associated with B Z disturbance and local current density enhancement, but to a lesser degree. Hence, current sheet disturbances induced by initial dipolarization pulses could differ, depending on the configuration of the current sheet.

Subfields: Astronomy and Astrophysics, Geophysics

View Paper: https://www.semanticscholar.org/paper/cbe857e2532d37b4d97239e9f2708b07bda56b49

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Geophysics

Citations in the corpus

Fermi and betatron acceleration of suprathermal electrons behind dipolarization fronts (2011, background): “[2] The dipolarization front (DF), the earthward leading edge of the re‐configurated magnetic field after reconnection in the magnetotail, has been extensively studied recently together with the co‐existing wave activity (lower hybrid, whistlers, and electron cyclotron harmonic mode) and plasma dyna”
Substorm Current Wedge Revisited (2015, background): “Multiple Earthward moving dipolarization fronts and tailward progressing dipolarized regions due to flux pileup have both been detected within a substorm (Nakamura et al. 2009).”
Occurrence rate of earthward‐propagating dipolarization fronts (2012, background): “The evolution processes of the DF frommiddle tail to the near-Earth region [e.g., Runov et al., 2009; Nakamura et al., 2009], and the relation between the DF and the aurora [e.g., Volwerk et al., 2008; Sakaguchi et al., 2011] are also studied.”