The quasi-adiabatic ion distribution in the central plasma sheet and its boundary layer

1991 ◽  
Vol 96 (A2) ◽  
pp. 1601-1609 ◽  
Author(s):  
Maha Ashour-Abdalla ◽  
Jorg Büchner ◽  
Lev M. Zelenyi
Keyword(s):  
Boundary Layer ◽  
Plasma Sheet ◽  
Ion Distribution ◽  
Central Plasma ◽  
Central Plasma Sheet

scholarly journals Travelling convection vortices in the ionosphere map to the central plasma sheet

1996 ◽  
Vol 14 (10) ◽  
pp. 1025-1031 ◽  
Author(s):  
A. Yahnin ◽  
T. Moretto
Keyword(s):  
Boundary Layer ◽  
Plasma Sheet ◽  
Satellite Measurements ◽  
Low Latitude ◽  
Central Plasma ◽  
Precipitation Boundary ◽  
Boundary Plasma ◽  
Central Plasma Sheet ◽  
Low Altitude ◽  
Low Latitude Boundary Layer

Abstract. We investigate the magnetospheric domain responsible for the generation of ionospheric travelling convection vortices (TCV) by comparing the location of the TCV to the locations of the low-altitude particle-precipitation boundaries deduced from the DMSP satellite measurements. For three very well documented TCV events we are able to identify suitable satellite passes, in the sense that for each event we can identify two to three passes occurring close to the TCV observation in both time and space. In all three cases the comparisons place the TCV centres at or equatorward of the central plasma sheet/boundary plasma sheet precipitation boundary. Thus our results indicate that the field-aligned currents related to the TCV originate in the plasma sheet rather than at the magnetopause or in the low-latitude boundary layer, as previous studies suggest.

scholarly journals On energetic electrons (>38 keV) in the central plasma sheet: Data analysis and modeling

2011 ◽  
Vol 116 (A9) ◽  
pp. n/a-n/a ◽  
Author(s):  
Bingxian Luo ◽  
Weichao Tu ◽  
Xinlin Li ◽  
Jiancun Gong ◽  
Siqing Liu ◽  
...  
Keyword(s):  
Data Analysis ◽  
Plasma Sheet ◽  
Energetic Electrons ◽  
Central Plasma ◽  
Central Plasma Sheet

scholarly journals Dispersive O<sup>+</sup> conics observed in the plasma-sheet boundary layer with CRRES/LOMICS during a magnetic storm

1996 ◽  
Vol 14 (6) ◽  
pp. 593-607
Author(s):  
M. Wüest ◽  
D. T. Young ◽  
M. F. Thomsen ◽  
B. L. Barraclough ◽  
H. J. Singer ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Plasma Sheet ◽  
Pitch Angle ◽  
Radiation Effects ◽  
Low Frequency ◽  
Particle Interactions ◽  
Plasma Sheet Boundary Layer ◽  
Angle Scattering ◽  
Central Plasma ◽  
Spacecraft Spin

Abstract. We present initial results from the Low-energy magnetospheric ion composition sensor (LOMICS) on the Combined release and radiation effects satellite (CRRES) together with electron, magnetic field, and electric field wave data. LOMICS measures all important magnetospheric ion species (H+, He++, He+, O++, O+) simultaneously in the energy range 60 eV to 45 keV, as well as their pitch-angle distributions, within the time resolution afforded by the spacecraft spin period of 30 s. During the geomagnetic storm of 9 July 1991, over a period of 42 min (0734 UT to 0816 UT) the LOMICS ion mass spectrometer observed an apparent O+ conic flowing away from the southern hemisphere with a bulk velocity that decreased exponentially with time from 300 km/s to 50 km/s, while its temperature also decreased exponentially from 700 to 5 eV. At the onset of the O+ conic, intense low-frequency electromagnetic wave activity and strong pitch-angle scattering were also observed. At the time of the observations the CRRES spacecraft was inbound at L~7.5 near dusk, magnetic local time (MLT), and at a magnetic latitude of –23°. Our analysis using several CRRES instruments suggests that the spacecraft was skimming along the plasma sheet boundary layer (PSBL) when the upward-flowing ion conic arrived. The conic appears to have evolved in time, both slowing and cooling, due to wave-particle interactions. We are unable to conclude whether the conic was causally associated with spatial structures of the PSBL or the central plasma sheet.

Nonadiabatic heating of the central plasma sheet at substorm onset

1992 ◽  
Vol 97 (A2) ◽  
pp. 1481 ◽  
Author(s):  
C. Y. Huang ◽  
L. A. Frank ◽  
G. Rostoker ◽  
J. Fennell ◽  
D. G. Mitchell
Keyword(s):  
Plasma Sheet ◽  
Substorm Onset ◽  
Central Plasma ◽  
Central Plasma Sheet

Mapping of the statistical auroral distribution into the magnetosphere

1994 ◽  
Vol 72 (5-6) ◽  
pp. 266-269 ◽  
Author(s):  
Y. I. Feldstein ◽  
R. D. Elphinstone ◽  
D. J. Hearn ◽  
J. S. Murphree ◽  
L. L. Cogger
Keyword(s):  
Plasma Sheet ◽  
Large Scale ◽  
Source Region ◽  
Central Plasma ◽  
Discrete Structures ◽  
Central Plasma Sheet ◽  
Auroral Emissions ◽  
Auroral Arcs ◽  
Inner Region ◽  
Entry Layer

Statistical auroral distributions are used in combination with an empirical model of the Earth's magnetic field in an attempt to determine the large-scale magnetospheric source regions for various types of auroral luminosity. The narrow ring of structured auroral emissions during magnetically quiet intervals appears to be associated with the inner region of the nightside central plasma sheet and the dayside entry layer. Under active conditions these discrete structures expand to fill the entire central plasma sheet. The high-altitude boundary plasma sheet on the other hand is more likely to be related to diffuse auroral emissions poleward of this "oval" and to high-latitude polar auroral arcs. Under this scenario, the region of the magnetosphere bounded by the inner edge of the tail current sheet, the plasmasphere, and the dayside entry layer is the source region for the most equatorward diffuse auroral precipitation.

Statistical Properties of Field-Aligned Currents in the Plasma Sheet Boundary Layer

2020 ◽  
Author(s):  
Yuanqiang Chen ◽  
Mingyu Wu ◽  
Guoqiang Wang ◽  
Zonghao Pan ◽  
Tielong Zhang
Keyword(s):  
Boundary Layer ◽  
Southern Hemisphere ◽  
Geomagnetic Activity ◽  
Plasma Sheet ◽  
Flank Region ◽  
Distribution Patterns ◽  
Occurrence Rate ◽  
Small Scale ◽  
Plasma Sheet Boundary Layer ◽  
Central Plasma

&lt;p&gt;Field-aligned currents (FACs), also known as Birkeland currents, are the agents by which momentum and energy can be transferred to the ionosphere from solar wind and the magnetosphere, exhibiting a seasonal variation as that of ionospheric conductance at low altitude. By using magnetic field and plasma measurements from the Magntospheric Multiscale (MMS), we estimated the properties of the small-scale FACs in the plasma sheet boundary layer (PSBL) region. The occurrence rates of those FACs are larger near the midnight plane and near the flank region; they are also larger in the northern (summer) hemisphere than in the southern hemisphere, especially for the earthward FACs. Different distribution patterns as a function of plasma &amp;#946; are found for the Beam-type FACs and the Flow-type FACs (accompanied with observable perpendicular currents). The latter are closer to central plasma sheet (higher &amp;#946;) and their occurrence rate decreases linearly toward tail lobe (lower &amp;#946;), while the former mainly appear within the &amp;#946; range of 0.1 to 1. FAC magnitudes show little dependence on plasma &amp;#946;, while they would increase when approaching Earth generally. The occurrence rate and magnitude of FACs both increase from low to high geomagnetic activity, consistent with observation at ionospheric altitude. The main carriers for FACs in PSBL are thermal electrons, while cold electrons sometimes could also have contribution, especially under high geomagnetic activity. This study shows that FACs in the PSBL exhibit an asymmetry of occurrence rate between the northern and southern hemisphere and different signatures under low and high geomagnetic activity, which are consistent with FACs at ionospheric altitude. This demonstrates that FACs are significant in magnetosphere-ionosphere coupling and illustrates the possible ionospheric feedback effects to magnetosphere in the nightside.&lt;/p&gt;

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