scholarly journals Temperature anisotropies of electrons and two-component protons in the dusk plasma sheet

2007 ◽  
Vol 25 (6) ◽  
pp. 1417-1432 ◽  
Author(s):  
M. N. Nishino ◽  
M. Fujimoto ◽  
T. Terasawa ◽  
G. Ueno ◽  
K. Maezawa ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Solar Wind ◽  
Magnetic Reconnection ◽  
Plasma Sheet ◽  
Cold Plasma ◽  
Strong Anisotropy ◽  
Low Latitude ◽  
Selective Heating ◽  
Two Component ◽  
Low Latitude Boundary Layer

Abstract. To investigate the cold plasma sheet formation under northward IMF, we study the temperature anisotropies of electrons and two-component protons observed by the Geotail spacecraft. The two-component protons, which are occasionally observed in the dusk plasma sheet near the low-latitude boundary, are the result of spatial mixing of the hot protons of the magnetosphere proper and the cold protons from the solar wind. Recent research focusing on the two-component protons reported that the cold proton component at times has a strong anisotropy, and that the sense of the anisotropy depends on the observed locations. Since electrons have been known to possess a strong parallel anisotropy around the low-latitude boundary layer, we compare anisotropies of electrons and protons to find that the strengths of parallel anisotropies of electrons and the cold proton component are in good correlation in the tail flank. The parallel anisotropy of electrons is stronger than that of the cold proton component, which is attributed to selective heating of electrons. We further find that the strengths of the parallel anisotropies in the tail flank depend on the latitudinal angle of the IMF; strong parallel anisotropies occur under strongly northward IMF. We discuss that the Kelvin-Helmholtz vortices, which developed under strongly northward IMF, and the resultant magnetic reconnection therein may lead to the strong parallel anisotropies observed in the tail flank.

scholarly journals Geotail observations of temperature anisotropy of the two-component protons in the dusk plasma sheet

2007 ◽  
Vol 25 (3) ◽  
pp. 769-777 ◽  
Author(s):  
M. N. Nishino ◽  
M. Fujimoto ◽  
T. Terasawa ◽  
G. Ueno ◽  
K. Maezawa ◽  
...  
Keyword(s):  
Solar Wind ◽  
Plasma Sheet ◽  
Transport Process ◽  
Cold Plasma ◽  
Strong Anisotropy ◽  
Temperature Anisotropy ◽  
Low Latitude ◽  
Two Component ◽  
Cold Component

Abstract. In search for clues towards the understanding of the cold plasma sheet formation under northward IMF, we study the temperature anisotropy of the two-component protons in the plasma sheet near the dusk low-latitude boundary observed by the Geotail spacecraft. The two-component protons result from mixing of the cold component from the solar wind and the hot component of the magnetospheric origin, and may be the most eloquent evidence for the transport process across the magnetopause. The cold component occasionally has a strong anisotropy in the dusk flank, and the sense of the anisotropy depends on the observed locations: the parallel temperature is enhanced in the tail flank while the perpendicular temperature is enhanced on the dayside. The hot component is nearly isotropic in the tail while the perpendicular temperature is enhanced on the dayside. We discuss possible mechanism that can lead to the observed temperature anisotropies.

scholarly journals Region-1 field aligned currents in experiments on laser-produced plasma interacting with magnetic dipole

2010 ◽  
Vol 6 (S274) ◽  
pp. 40-43
Author(s):  
I. F. Shaikhislamov ◽  
Yu. P. Zakharov ◽  
V. G. Posukh ◽  
E. L. Boyarintsev ◽  
A. V. Melekhov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Boundary Layer ◽  
Solar Wind ◽  
Experimental Evidence ◽  
Magnetic Dipole ◽  
Present Report ◽  
Low Latitude ◽  
The Earth ◽  
Field Aligned Current ◽  
Low Latitude Boundary Layer

AbstractIn previous experiments by the authors a generation of intense field aligned current (FAC) system on Terrella poles was observed. In the present report a question of these currents origin in a low latitude boundary layer of magnetosphere is investigated. Experimental evidence of such a link was obtained by measurements of magnetic field generated by tangential sheared drag. Results suggest that compressional and Alfven waves are responsible for FAC generation. The study is most relevant to FAC generation in the Earth and Hermean magnetospheres following pressure jumps in Solar Wind.

The low-latitude boundary layer and the boundary plasma sheet at low altitude: Prenoon precipitation regions and convection reversal boundaries

1991 ◽  
Vol 96 (A12) ◽  
pp. 21013 ◽  
Author(s):  
Patrick T. Newell ◽  
William J. Burke ◽  
Ennio R. Sánchez ◽  
Ching-I. Meng ◽  
Marian E. Greenspan ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Plasma Sheet ◽  
Low Latitude ◽  
Boundary Plasma ◽  
Low Altitude ◽  
Low Latitude Boundary Layer

scholarly journals Geotail observations of two-component protons in the midnight plasma sheet

2007 ◽  
Vol 25 (10) ◽  
pp. 2229-2245 ◽  
Author(s):  
M. N. Nishino ◽  
M. Fujimoto ◽  
G. Ueno ◽  
K. Maezawa ◽  
T. Mukai ◽  
...  
Keyword(s):  
High Latitude ◽  
Plasma Sheet ◽  
Transport Process ◽  
Cold Plasma ◽  
Plasma Transport ◽  
Helmholtz Instability ◽  
Low Latitude ◽  
Vortical Structures ◽  
Two Component ◽  
To Come

Abstract. Through the effort to obtain clues toward understanding of transport of cold plasma in the near-Earth magnetotail under northward IMF, we find that two-component protons are observed in the midnight plasma sheet (−10>XGSM>−30 RE, |YGSM| <10 RE) under northward IMF by the Geotail spacecraft. Since the two-component protons are frequently observed on the duskside during northward IMF intervals but hardly on the dawnside, those found in the midnight plasma sheet are thought to come from the dusk flank. The cold proton component in the midnight region occasionally has a parallel anisotropy, which resembles that in the tail flank on the duskside. The flows in the plasma sheet with two-component protons were quite stagnant or slightly going dawnward, which supports the idea that the observed two-component protons in the midnight region are of duskside origin. Because the two-component protons in the midnight plasma sheet emerge under strongly northward IMF with the latitudinal angle larger than 45 degrees, and because the lag from the strongly northward IMF to the emergence can be as short as a few hours, we suggest that prompt plasma transport from the dusk to midnight region occurs under strongly northward IMF. We propose that the dawnward flows result from viscous interaction between the high-latitude portion of the plasma sheet and the lobe cell. Another candidate for plasma transport process from the dusk to the midnight region is turbulent flow due to vortical structures of the Kelvin-Helmholtz instability that developed around the dusk low-latitude boundary under strongly northward IMF. In addition, we also suggest that gradual cooling of hot protons under northward IMF is a global phenomenon in the near-Earth magnetotail.

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