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

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.

2000 ◽  
Vol 18 (1) ◽  
pp. 74-80 ◽  
Author(s):  
S. T. Berry ◽  
L. Kersley ◽  
J. Moen ◽  
W. F. Denig

Abstract. Spatial structures in ionospheric electron density revealed in a tomographic image have been identified with auroral forms and related to their sources in precipitating particles observed by DMSP satellites. The observations of plasma enhancements relate to discrete auroral arcs seen in the post-noon sector, identified by both red- and green-line emissions measured by a meridional scanning photometer. The features lie within a very narrow latitudinal band on L-shells where the satellite detectors observed electron precipitation classified as from the boundary plasma sheet (BPS). The harder particles are identified with an E-region structure, while further north the precipitation is softer, resulting in a localised F-layer blob and 630.0 nm emissions. A steep gradient in plasma density represent a signature in the ionosphere of the central plasma sheet (CPS)/BPS boundary. A transition to a less-structured F-layer is found on crossing the convection reversal boundary..Key words. Ionosphere (auroral ionosphere; ionosphere-magnetosphere interactions; polar ionosphere)


2011 ◽  
Vol 116 (A9) ◽  
pp. n/a-n/a ◽  
Author(s):  
Bingxian Luo ◽  
Weichao Tu ◽  
Xinlin Li ◽  
Jiancun Gong ◽  
Siqing Liu ◽  
...  

1991 ◽  
Vol 96 (A2) ◽  
pp. 1601-1609 ◽  
Author(s):  
Maha Ashour-Abdalla ◽  
Jorg Büchner ◽  
Lev M. Zelenyi

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

2004 ◽  
Vol 22 (4) ◽  
pp. 1061-1075 ◽  
Author(s):  
A. Grocott ◽  
T. K. Yeoman ◽  
R. Nakamura ◽  
S. W. H. Cowley ◽  
H. U. Frey ◽  
...  

Abstract. On 07 September 2001 the Cluster spacecraft observed a "bursty bulk flow" event in the near-Earth central plasma sheet. This paper presents a detailed study of the coincident ground-based observations and attempts to place them within a simple physical framework. The event in question occurs at ~22:30 UT, some 10min after a southward turning of the IMF. IMAGE and SAMNET magnetometer measurements of the ground magnetic field reveal perturbations of a few tens of nT and small amplitude Pi2 pulsations. CUTLASS radar observations of ionospheric plasma convection show enhanced flows out of the polar cap near midnight, accompanied by an elevated transpolar voltage. Optical data from the IMAGE satellite also show that there is a transient, localised ~1 kR brightening in the UV aurora. These observations are consistent with the earthward transport of plasma in the tail, but also indicate the absence of a typical "large-scale" substorm current wedge. An analysis of the field-aligned current system implied by the radar measurements does suggest the existence of a small-scale current "wedgelet", but one which lacks the global scale and high conductivities observed during substorm expansions. Key words. Ionosphere (auroral ionosphere; ionospheremagnetosphere interactions; plasma convection)


1989 ◽  
Vol 94 (A6) ◽  
pp. 6597-6606 ◽  
Author(s):  
W. Baumjohann ◽  
G. Paschmann ◽  
C. A. Cattell

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