New technique to calculate electron Alfvén layer and its application in interpreting geosynchronous access of PS energetic electrons. Issue 3 (9th March 2015)

• Record Type: Journal Article
• Authors: Zhang, D.; Cao, J. B.; Wei, X. H.; Li, L. Y.
• Is Part Of: Journal of geophysical research. Volume 120:Issue 3(2015:Mar.)
• Page Start: 1675
• Page End: 1683
• Publication Date: 2015-03-09
• Subjects: Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1002/2014JA020670
• Languages: English
• ISSNs: 2169-9380

Abstract

<abstract abstract-type="main" id="jgra51640-abs-0001"> <title>Abstract</title> <p id="jgra51640-para-0001">The magnetospheric particle drift theory in (<italic>U</italic>, <italic>B</italic>) coordinates provides a convenient tool for analyzing particle drift trajectories from plasma sheet to the inner magnetosphere. However, in this drift theory, the Alfvén layer for a realistic asymmetric magnetic field model cannot be obtained due to numerical difficulty. In this paper, we developed a new technique to calculate electron Alfvén layer for Volland‐Stern electrical potential model and dipole + T89 geomagnetic field model. The results show that for realistic asymmetric field models, the dawn and dusk separators are not in the dawn‐dusk meridian but asymmetric and tilt toward the dayside. The stagnant point of the electron Alfvén layer is always located in the duskside separator. Compared with the electron Alfvén layers calculated from Volland‐Stern electric field model and dipole magnetic field model, the new electron Alfvén layer becomes closer to the Earth and meanwhile rotates clockwise. This rotation makes the point closest to the Earth in the Alfvén layer shift from dawnside to nightside. The newly calculated geosynchronous Alfvén layer crossings cannot only explain the observed geosynchronous access of plasma sheet thermal (0.913 and 2.783 keV) electrons as previous studies did but also the geosynchronous access of plasma sheet energetic (10.472 and 31.039 keV) electrons. This new technique can be used to calculate Alfvén layer for any asymmetric field models and may become an important compliment to the classical magnetospheric particle drift theory in the (<italic>U</italic>, <italic>B</italic>) coordinates.</p> </abstract>