Consequences of violation of frozen‐in‐flux: Evidence from OpenGGCM simulations

作者: B. Hu , R. A. Wolf , F. R. Toffoletto , J. Yang , J. Raeder

DOI: 10.1029/2011JA016667

关键词: SubstormMagnetohydrodynamicsClassical mechanicsMagnetic reconnectionConvectionMechanicsInstabilityPhysicsField lineMagnetic fieldCurrent sheet

摘要: [1] It is widely believed that during a substorm, plasma instabilities occur before the onset of magnetic reconnection, signaling end growth phase. Despite many years effort, however, details how instability and reconnection develop from closed field line configuration with finite normal are not well understood. In this paper, we study an idealized simulation substorm occurred on 23 March 2007, based Open Geospace General Circulation Model (OpenGGCM). Our analysis emphasizes time development distribution entropy parameter its convective derivative, which should be zero in ideal MHD. late phase, exhibits, over range local times, systematic violation conservation corresponds to what called “antidiffusion.” Out background, more localized disturbance develops region high stretching, resulting formation strong reduction (bubble) earthward enhancement (blob). The process accelerated when current density exceeds threshold for triggering explicit resistivity code. bubble moves blob tailward, leads thinning sheet between them, making magnetospheric conducive tearing other (we do address specifically has occurred). This positive feedback gives rise increased perfect conductivity relation eventually reconnection.

参考文章(21)
M. I. Sitnov, K. Schindler, Tearing stability of a multiscale magnetotail current sheet Geophysical Research Letters. ,vol. 37, ,(2010) , 10.1029/2010GL042961
Joachim Raeder, Global Magnetohydrodynamics — A Tutorial LNP. ,vol. 615, pp. 212- 246 ,(2003) , 10.1007/3-540-36530-3_11
J. Yang, R. A. Wolf, F. R. Toffoletto, Accelerated thinning of the near‐Earth plasma sheet caused by a bubble‐blob pair Geophysical Research Letters. ,vol. 38, ,(2011) , 10.1029/2010GL045993
V.A. Sergeev, W. Lennartsson, Plasma sheet at X ≈ −20 RE during steady magnetospheric convection Planetary and Space Science. ,vol. 36, pp. 353- 370 ,(1988) , 10.1016/0032-0633(88)90124-9
C. Portier, Discussion and summary Radiation Protection Dosimetry. ,vol. 132, pp. 273- 274 ,(2008) , 10.1093/RPD/NCN282
Joachim Raeder, Douglas Larson, Wenhui Li, Emil L. Kepko, Timothy Fuller-Rowell, OpenGGCM Simulations for the THEMIS Mission Space Science Reviews. ,vol. 141, pp. 535- 555 ,(2008) , 10.1007/S11214-008-9421-5
B. Hu, F. R. Toffoletto, R. A. Wolf, S. Sazykin, J. Raeder, D. Larson, A. Vapirev, One-way coupled OpenGGCM/RCM simulation of the 23 March 2007 substorm event Journal of Geophysical Research. ,vol. 115, ,(2010) , 10.1029/2010JA015360
J. Birn, M. Hesse, K. Schindler, S. Zaharia, Role of entropy in magnetotail dynamics Journal of Geophysical Research: Space Physics. ,vol. 114, pp. n/a- n/a ,(2009) , 10.1029/2008JA014015
C. A. Cattell, Experimental evaluation of the Lundquist number for the Earth's magnetopause and magnetotail Journal of Geophysical Research: Space Physics. ,vol. 101, pp. 27309- 27316 ,(1996) , 10.1029/96JA02448