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

The Effect of Solar Wind Mach Numbers on the Occurrence Rate of Flux Transfer Events at the Dayside Magnetopause

2019 ◽  
Vol 46 (8) ◽  
pp. 4106-4113 ◽  
Author(s):  
C. Chen ◽  
T. R. Sun ◽  
C. Wang ◽  
Z. H. Huang ◽  
B. B. Tang ◽  
...  
Keyword(s):  
Solar Wind ◽  
Occurrence Rate ◽  
Flux Transfer Events ◽  
Dayside Magnetopause ◽  
Mach Numbers ◽  
Flux Transfer

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 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.

Plasma and magnetic field characteristics of magnetic flux transfer events

1982 ◽  
Vol 87 (A4) ◽  
pp. 2159 ◽  
Author(s):  
G. Paschmann ◽  
G. Haerendel ◽  
I. Papamastorakis ◽  
N. Sckopke ◽  
S. J. Bame ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Flux Transfer Events ◽  
Flux Transfer

scholarly journals Generation of Inverted Heliospheric Magnetic Flux by Coronal Loop Opening and Slow Solar Wind Release

2018 ◽  
Vol 868 (1) ◽  
pp. L14 ◽  
Author(s):  
Mathew J. Owens ◽  
Mike Lockwood ◽  
Luke A. Barnard ◽  
Allan R. MacNeil
Keyword(s):  
Solar Wind ◽  
Magnetic Flux ◽  
Coronal Loop ◽  
Slow Solar Wind

scholarly journals MESSENGER observations of planetary ion enhancements at Mercury’s northern magnetospheric cusp during Flux Transfer Event Showers

2021 ◽  
Author(s):  
Weijie Sun ◽  
James Slavin ◽  
Anna Milillo ◽  
Ryan Dewey ◽  
Stefano Orsini ◽  
...  
Keyword(s):  
Solar Wind ◽  
Large Scale ◽  
Transfer Event ◽  
Order Of Magnitude ◽  
In Situ Observations ◽  
Flux Transfer ◽  
Magnetospheric Cusp ◽  
Upward Moving ◽  
Entry Layer

Abstract At Mercury, several processes can release ions and neutrals out of the planet’s surface. Here we present enhancements of dayside planetary ions in the solar wind entry layer during flux transfer event (FTE) “showers” near Mercury’s northern magnetospheric cusp. In this entry layer, solar wind ions are accelerated and move downward (i.e. planetward) toward the cusps, which sputter upward-moving planetary ions within 1 minute. The precipitation rate is enhanced by an order of magnitude during FTE showers and the neutral density of the exosphere can vary by >10% due to this FTE-driven sputtering. These in situ observations of enhanced planetary ions in the entry layer likely correspond to an escape channel of Mercury’s planetary ions, and the large-scale variations of the exosphere observed on minute-timescales by ground-based telescopes. Comprehensive, future multi-point measurements made by BepiColombo will greatly enhance our understanding of the processes contributing to Mercury’s dynamic exosphere and magnetosphere.

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.

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