scholarly journals Characteristics of solar wind control on Jovian UV auroral activity deciphered by long-term Hisaki EXCEED observations: Evidence of preconditioning of the magnetosphere?

2016 ◽  
Vol 43 (13) ◽  
pp. 6790-6798 ◽  
Author(s):  
Hajime Kita ◽  
Tomoki Kimura ◽  
Chihiro Tao ◽  
Fuminori Tsuchiya ◽  
Hiroaki Misawa ◽  
...  
Keyword(s):  
Solar Wind ◽  
Auroral Activity

scholarly journals Dayside auroral activity and magnetic flux transfer from the solar wind

1989 ◽  
Vol 16 (1) ◽  
pp. 33-36 ◽  
Author(s):  
M. Lockwood ◽  
P. E. Sandholt ◽  
S. W. H. Cowley
Keyword(s):  
Solar Wind ◽  
Magnetic Flux ◽  
Auroral Activity ◽  
Flux Transfer

scholarly journals Detailed dayside auroral morphology as a function of local time for southeast IMF orientation: implications for solar wind-magnetosphere coupling

2004 ◽  
Vol 22 (10) ◽  
pp. 3537-3560 ◽  
Author(s):  
P. E. Sandholt ◽  
C. J. Farrugia ◽  
W. F. Denig
Keyword(s):  
Solar Wind ◽  
Local Time ◽  
High Latitude ◽  
Specific Activity ◽  
Moderate Intensity ◽  
Auroral Activity ◽  
Activity Intensity ◽  
Subsolar Point ◽  
Field Lines ◽  
Ground Magnetic

Abstract. In two case studies we elaborate on spatial and temporal structures of the dayside aurora within 08:00-16:00 magnetic local time (MLT) and discuss the relationship of this structure to solar wind-magnetosphere interconnection topology and the different stages of evolution of open field lines in the Dungey convection cycle. The detailed 2-D auroral morphology is obtained from continuous ground observations at Ny Ålesund (76° magnetic latitude (MLAT)), Svalbard during two days when the interplanetary magnetic field (IMF) is directed southeast (By>0; Bz<0). The auroral activity consists of the successive activations of the following forms: (i) latitudinally separated, sunward moving, arcs/bands of dayside boundary plasma sheet (BPS) origin, in the prenoon (08:00-11:00 MLT) and postnoon (12:00-16:00 MLT) sectors, within 70-75° MLAT, (ii) poleward moving auroral forms (PMAFs) emanating from the pre- and postnoon brightening events, and (iii) a specific activity appearing in the 07:00-10:00 MLT/75-80° MLAT during the prevailing IMF By>0 conditions. The pre- and postnoon activations are separated by a region of strongly attenuated auroral activity/intensity within the 11:00-12:00 MLT sector, often referred to as the midday gap aurora. The latter aurora is attributed to the presence of component reconnection at the subsolar magnetopause where the stagnant magnetosheath flow lead to field-aligned currents (FACs) which are of only moderate intensity. The much more active and intense aurorae in the prenoon (07:00-11:00 MLT) and postnoon (12:00-16:00 MLT) sectors originate in magnetopause reconnection events that are initiated well away from the subsolar point. The high-latitude auroral activity in the prenoon sector (feature iii) is found to be accompanied by a convection channel at the polar cap boundary. The associated ground magnetic deflection (DPY) is a Svalgaard-Mansurov effect. The convection channel is attributed to effective momentum transfer from the solar wind-magnetosphere dynamo in the high-latitude boundary layer (HBL), on the downstream side of the cusp.

Long-Term Variability of the Polytropic Index of Solar Wind Protons at 1 AU

Solar Physics ◽  
2013 ◽  
Vol 289 (4) ◽  
pp. 1371-1378 ◽  
Author(s):  
G. Nicolaou ◽  
G. Livadiotis ◽  
X. Moussas
Keyword(s):  
Solar Wind ◽  
Polytropic Index

The Long Term Cosmic Ray Variation Relevant to Solar Wind Structure in the Outer Heliosphere

1990 ◽  
pp. 199-203
Author(s):  
M.V. Alania ◽  
R.G. Aslamazashvili ◽  
T.B. Bochorishvili ◽  
L.I. Dorman ◽  
R.T. Guschina ◽  
...  
Keyword(s):  
Solar Wind ◽  
Cosmic Ray ◽  
Outer Heliosphere ◽  
Wind Structure ◽  
Solar Wind Structure

Long-term cosmic ray/solar activity hysteresis phenomenon and properties of solar wind for the last 200 years

1999 ◽  
Author(s):  
L. I. Dorman ◽  
G. Villoresi ◽  
I. V. Dorman ◽  
N. Iucci ◽  
M. Parisi
Keyword(s):  
Solar Wind ◽  
Solar Activity ◽  
Cosmic Ray ◽  
Hysteresis Phenomenon

scholarly journals Simulating the Reiner Gamma Swirl: The Long‐Term Effect of Solar Wind Standoff

2020 ◽  
Vol 125 (5) ◽  
Author(s):  
J. Deca ◽  
D. J. Hemingway ◽  
A. Divin ◽  
C. Lue ◽  
A. R. Poppe ◽  
...  
Keyword(s):  
Solar Wind ◽  
Term Effect ◽  
Long Term Effect

scholarly journals A statistical study of the long-term evolution of coronal hole properties as observed by SDO

2020 ◽  
Vol 638 ◽  
pp. A68 ◽  
Author(s):  
S. G. Heinemann ◽  
V. Jerčić ◽  
M. Temmer ◽  
S. J. Hofmeister ◽  
M. Dumbović ◽  
...  
Keyword(s):  
Solar Wind ◽  
Magnetic Flux ◽  
Coronal Hole ◽  
High Speed ◽  
Coronal Holes ◽  
Magnetic Flux Density ◽  
High Speed Stream ◽  
Term Evolution ◽  
Hole Area

Context. Understanding the evolution of coronal holes is especially important when studying the high-speed solar wind streams that emanate from them. Slow- and high-speed stream interaction regions may deliver large amounts of energy into the Earth’s magnetosphere-ionosphere system, cause geomagnetic storms, and shape interplanetary space. Aims. By statistically investigating the long-term evolution of well-observed coronal holes we aim to reveal processes that drive the observed changes in the coronal hole parameters. By analyzing 16 long-living coronal holes observed by the Solar Dynamic Observatory, we focus on coronal, morphological, and underlying photospheric magnetic field characteristics, and investigate the evolution of the associated high-speed streams. Methods. We use the Collection of Analysis Tools for Coronal Holes to extract and analyze coronal holes using 193 Å EUV observations taken by the Atmospheric Imaging Assembly as well as line–of–sight magnetograms observed by the Helioseismic and Magnetic Imager. We derive changes in the coronal hole properties and look for correlations with coronal hole evolution. Further, we analyze the properties of the high–speed stream signatures near 1AU from OMNI data by manually extracting the peak bulk velocity of the solar wind plasma. Results. We find that the area evolution of coronal holes shows a general trend of growing to a maximum followed by a decay. We did not find any correlation between the area evolution and the evolution of the signed magnetic flux or signed magnetic flux density enclosed in the projected coronal hole area. From this we conclude that the magnetic flux within the extracted coronal hole boundaries is not the main cause for its area evolution. We derive coronal hole area change rates (growth and decay) of (14.2 ± 15.0)×108 km2 per day showing a reasonable anti-correlation (ccPearson = −0.48) to the solar activity, approximated by the sunspot number. The change rates of the signed mean magnetic flux density (27.3 ± 32.2 mG day−1) and the signed magnetic flux (30.3 ± 31.5 1018 Mx day−1) were also found to be dependent on solar activity (ccPearson = 0.50 and ccPearson = 0.69 respectively) rather than on the individual coronal hole evolutions. Further we find that the relation between coronal hole area and high-speed stream peak velocity is valid for each coronal hole over its evolution, but we see significant variations in the slopes of the regression lines.

scholarly journals Helioseismology from space, the SOHO project

1988 ◽  
Vol 123 ◽  
pp. 545-548
Author(s):  
V. Domingo
Keyword(s):  
Solar Wind ◽  
Solar Corona ◽  
European Space Agency ◽  
Science Research ◽  
Small Scale ◽  
Heliospheric Observatory ◽  
Space Agency ◽  
Cluster A ◽  
Physics Programme

As a cornerstone of its long term plan for space science research, the European Space Agency (ESA) is developing the Solar Terrestrial Physics Programme that consists of two parts: one, the Solar and Heliospheric Observatory (SOHO) for the study of the solar internal structure and the physics of the solar corona and the solar wind, and another, CLUSTER, a series of four spacecraft flying in formation to study small scale plasma phenomena in several regions of the magnetosphere and in the near Earth solar wind. The feasibility of the missions was demonstrated in Phase A studies carried out by industrial consortia under the supervision of ESA (1,2). According to the current plans an announcement of opportunity calling for instrument proposals will be issued by ESA during the first quarter of 1987. It is foreseen that the spacecraft will be launched by the end of 1994.

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