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Title: Larmor electric field observed at the Earth's magnetopause by Polar satellite

We present, for the first time, observational evidence of a kinetic electric field near the X-line associated with asymmetric reconnection at the Earth's dayside magnetopause using Polar observations. On March 29, 2003, Polar satellite detected an asymmetric collisionless reconnection event. This event shows a unipolar Hall electric field signature and a simple deviation from the guide field during the magnetopause crossing, with the absence of an ion plasma jet outflow indicating that the magnetopause crossing was near the X-line. As expected from particle-in-cell simulations by Malakit et al. (Phys. Rev. Lett. 111, 135001 (2013)), an earthward pointing normal electric field appears in the magnetospheric side of the ion diffusion region. The electric field satisfies two necessary conditions for the existence of the finite ion Larmor radius effect: (1) the ion Larmor radius (r{sub g2}) is larger than the distance between the stagnation point and the edge of the ion diffusion region in the strong magnetic field side (δ{sub S2}) and (2) the spatial extent of the kinetic electric field (δ{sub EL}) is of the order of the ion Larmor radius. Furthermore, it is shown that the peak value of the Larmor electric field is comparable to the predicted value. Themore » observation of the Larmor electric field can be valuable in other analyses to show that the crossing occurred near the X-line.« less
Authors:
; ;  [1] ;  [2] ;  [3]
  1. National Institute for Space Research - INPE, São José dos Campos, São Paulo (Brazil)
  2. Space Sciences Laboratory, University of California, Berkeley, California 94720 (United States)
  3. School of Engineering - EEL, University of São Paulo, Lorena, São Paulo (Brazil)
Publication Date:
OSTI Identifier:
22300235
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 21; Journal Issue: 10; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ASYMMETRY; COMPARATIVE EVALUATIONS; DIFFUSION; ELECTRIC FIELDS; IONS; LARMOR RADIUS; MAGNETIC FIELDS; MAGNETOPAUSE; PLASMA JETS; SATELLITES; SIMULATION; STAGNATION POINT