The ultraviolet imager experiment on the Swedish Viking satellite: Contributions to auroral physics

1991 ◽  
Vol 69 (8-9) ◽  
pp. 1032-1039 ◽  
Author(s):  
L. L. Cogger ◽  
J. S. Murphree ◽  
R. D. Elphinstone ◽  
D. J. Hearn ◽  
R. A. King
Keyword(s):  
Magnetic Field ◽  
Interplanetary Magnetic Field ◽  
Data Base ◽  
Real Time ◽  
Large Scale ◽  
Detailed Knowledge ◽  
Rapid Changes ◽  
Temporal And Spatial ◽  
Auroral Physics ◽  
Rich Data

The ultraviolet imager on board the Swedish Viking satellite was designed to provide real-time monitoring of the auroral distribution from space. This objective was achieved over the nominal lifetime of the satellite, March–December, 1986 during which period approximately 45 000 auroral images were acquired. A number of technical and operational innovations have resulted in a rich data base for studies of auroral and magnetospheric processes. Some of the significant scientific advances that have resulted from the investigation of the temporal and spatial development of the auroral distribution include observations of rapid changes of dayside aurora, the effects of this distribution due to the interplanetary magnetic field, and more detailed knowledge of the substorm process. The utilization of models of the Earth's magnetic field to map auroral signatures to the corresponding magnetospheric regions has led to an increased understanding of the mechanisms associated with the large-scale auroral distribution.

About the Relation Between the Limb Effect of the Redshift on the Sun and the Large-Scale Distribution of Solar activity

1976 ◽  
Vol 71 ◽  
pp. 113-118
Author(s):  
P. Ambrož
Keyword(s):  
Magnetic Field ◽  
Solar Activity ◽  
Magnetic Fields ◽  
Interplanetary Magnetic Field ◽  
Large Scale ◽  
The Sun ◽  
Limb Effect

The measurement of the magnitude of the limb effect was homogenized in time and a recurrent period of maxima of 27.8 days was found. A relation was found between the maximum values of the limb effect of the redshift, the boundaries of polarities of the interplanetary magnetic field, the characteristic large-scale distribution of the background magnetic fields and the complex of solar activity.

scholarly journals Excitation of transient lobe cell convection and auroral arc at the cusp poleward boundary during a transition of the interplanetary magnetic field from south to north

2001 ◽  
Vol 19 (5) ◽  
pp. 487-493 ◽  
Author(s):  
P. E. Sandholt ◽  
C. J. Farrugia ◽  
S. W. H. Cowley ◽  
M. Lester ◽  
J.-C. Cerisier
Keyword(s):  
Magnetic Field ◽  
Interplanetary Magnetic Field ◽  
Large Scale ◽  
Intermediate Phase ◽  
Bright Spot ◽  
Convection Cell ◽  
Plasma Convection ◽  
Cell Pattern ◽  
Auroral Phenomena ◽  
Lobe Reconnection

Abstract. We document the activation of transient polar arcs emanating from the cusp within a 15 min long intermediate phase during the transition from a standard two-cell convection pattern, representative of a strongly southward interplanetary magnetic field (IMF), to a "reverse" two-cell pattern, representative of strongly northward IMF conditions. During the 2–3 min lifetime of the arc, its base in the cusp, appearing as a bright spot, moved eastward toward noon by ~ 300 km. As the arc moved, it left in its "wake" enhanced cusp precipitation. The polar arc is a tracer of the activation of a lobe convection cell with clockwise vorticity, intruding into the previously established large-scale distorted two-cell pattern, due to an episode of localized lobe reconnection. The lobe cell gives rise to strong flow shear (converging electric field) and an associated sheet of outflowing field-aligned current, which is manifested by the polar arc. The enhanced cusp precipitation represents, in our view, the ionospheric footprint of the lobe reconnection process.Key words. Magnetospheric physics (auroral phenomena; magnetopause, cusp, and boundary layers; plasma convection)

scholarly journals Active regions and the interplanetary magnetic field

1968 ◽  
Vol 35 ◽  
pp. 390-394
Author(s):  
John M. Wilcox ◽  
Norman F. Ness ◽  
Kenneth H. Schatten
Keyword(s):  
Magnetic Field ◽  
Interplanetary Magnetic Field ◽  
Large Scale ◽  
Early Stage ◽  
Active Regions ◽  
The Sun ◽  
Sector Structure ◽  
Archimedean Spiral ◽  
Spiral Angle ◽  
Scale Evolution

The relation of solar active regions to the large-scale sector structure of the interplanetary field is discussed. In the winter of 1963–64 (observed by the satellite IMP-1) the plage density was greatest in the leading portion of the sectors and lesser in the trailing portion of the sectors. The boundaries of the sectors (places at which the direction of the interplanetary magnetic field changed from toward the Sun to away from the Sun, or vice versa) were remarkably free of plages. The very fact that since the first observations in 1962 the average interplanetary field has almost always had the property of being either toward the Sun or away from the Sun (along the Archimedean spiral angle) continuously for several days must be considered in the discussion of large-scale evolution of active regions. Using the observed interplanetary magnetic field at 1 AU and a set of reasonable assumptions the magnetic configuration in the ecliptic from 0·4 AU to 1·2 AU has been reconstructed. In at least one case a pattern emerges which appears to be related to the evolution of an active region from an early stage in which the magnetic lines closely couple the preceding and following halves of the region to a later stage in which the two halves of the region are more widely separated.

Large scale response of the magnetosphere to a southward turning of the interplanetary magnetic field

1987 ◽  
Vol 92 (A3) ◽  
pp. 2365 ◽  
Author(s):  
J. A. Sauvaud ◽  
J. P. Treilhou ◽  
A. Saint-Marc ◽  
J. Dandouras ◽  
H. Rème ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Interplanetary Magnetic Field ◽  
Large Scale ◽  
Scale Response
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