scholarly journals Geomagnetic response at low latitude to continuous solar wind pressure variations during northward interplanetary magnetic field

1999 ◽  
Vol 104 (A9) ◽  
pp. 19923-19930 ◽  
Author(s):  
P. Francia ◽  
S. Lepidi ◽  
U. Villante ◽  
P. Di Giuseppe ◽  
A. J. Lazarus
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Interplanetary Magnetic Field ◽  
Wind Pressure ◽  
Low Latitude ◽  
Solar Wind Pressure

Photometry of dayside auroras during solar minimum 1This article is part of a Special issue that honours the work of Dr. Donald M. Hunten FRSC who passed away in December 2010 after a very illustrious career.

2012 ◽  
Vol 90 (8) ◽  
pp. 753-758 ◽  
Author(s):  
D.J. McEwen ◽  
G.G. Sivjee
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Interplanetary Magnetic Field ◽  
Solar Minimum ◽  
Dynamic Pressure ◽  
Wind Pressure ◽  
Special Issue ◽  
Solar Wind Pressure ◽  
The Many ◽  
Airglow Intensity

An examination is made of Antarctic dayside auroras to establish how they relate to solar wind strength under the quiet conditions of the recent extended solar minimum when the solar wind pressure was weak and the interplanetary magnetic field Bz is small. It is found that, during the many days of observation, the aurora is detected even with the most stable and quiet conditions. On such occasions the 630 nm OI emission can be as low as 50 R, but is unambiguously and continuously detectable through each noon. This is above an airglow intensity of about 30 R. For these quiet conditions there is no evident relation between the solar wind dynamic pressure or interplanetary magnetic field Bz and dayside auroral intensity. This suggests that there is no effective reconnection under these minimal conditions and the particle source for the dayside aurora could be within the magnetosphere.

scholarly journals Solar wind and substorm excitation of the wavy current sheet

2009 ◽  
Vol 27 (6) ◽  
pp. 2457-2474 ◽  
Author(s):  
C. Forsyth ◽  
M. Lester ◽  
R. C. Fear ◽  
E. Lucek ◽  
I. Dandouras ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Current Sheet ◽  
Pressure Pulse ◽  
Wind Pressure ◽  
Expansion Velocity ◽  
Solar Wind Pressure ◽  
Wave Models ◽  
Best Fit ◽  
The Magnetic Field

Abstract. Following a solar wind pressure pulse on 3 August 2001, GOES 8, GOES 10, Cluster and Polar observed dipolarizations of the magnetic field, accompanied by an eastward expansion of the aurora observed by IMAGE, indicating the occurrence of two substorms. Prior to the first substorm, the motion of the plasma sheet with respect to Cluster was in the ZGSM direction. Observations following the substorms show the occurrence of current sheet waves moving predominantly in the −YGSM direction. Following the second substorm, the current sheet waves caused multiple current sheet crossings of the Cluster spacecraft, previously studied by Zhang et al. (2002). We further this study to show that the velocity of the current sheet waves was similar to the expansion velocity of the substorm aurora and the expansion of the dipolarization regions in the magnetotail. Furthermore, we compare these results with the current sheet wave models of Golovchanskaya and Maltsev (2005) and Erkaev et al. (2008). We find that the Erkaev et al. (2008) model gives the best fit to the observations.

scholarly journals Induced and Permanent Magnetism on the Moon: Structural and Evolutionary Implications

1971 ◽  
Vol 2 ◽  
pp. 173-188
Author(s):  
C. P. Sonett ◽  
P. Dyal ◽  
D. S. Colburn ◽  
B. F. Smith ◽  
G. Schubert ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Dynamic Pressure ◽  
Wind Pressure ◽  
Dark Side ◽  
The Moon ◽  
Permanent Magnetic Field ◽  
Crustal Layer ◽  
Induced Field ◽  
Solar Wind Pressure

AbstractIt is shown that the Moon possesses an extraordinary response to induction from the solar wind due to a combination of a high interior electrical conductivity together with a relatively resistive crustal layer into which the solar wind dynamic pressure forces back the induced field. The dark side response, devoid of solar wind pressure, is approximately that expected for the vacuum case. These data permit an assessment of the interior conductivity and an estimate of the thermal gradient in the crustal region. The discovery of a large permanent magnetic field at the Apollo 12 site corresponds approximately to the paleomagnetic residues discovered in both Apollo 11 and 12 rock samples The implications regarding an early lunar magnetic field are discussed and it is shown that among the various conjectures regarding the early field the most prominent are either an interior dynamo or an early approach to the Earth though no extant model is free of difficulties.

scholarly journals The Earth's passage of the April 11, 1997 coronal ejecta: geomagnetic field fluctuations at high and low latitude during northward interplanetary magnetic field conditions

1999 ◽  
Vol 17 (10) ◽  
pp. 1245-1250 ◽  
Author(s):  
S. Lepidi ◽  
P. Francia ◽  
U. Villante ◽  
A. Meloni ◽  
A. J. Lazarus ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Interplanetary Magnetic Field ◽  
Geomagnetic Field ◽  
Field Conditions ◽  
Mhd Waves ◽  
Low Latitude ◽  
Terra Nova Bay ◽  
Field Fluctuations ◽  
Terra Nova

Abstract. An analysis of the low frequency geomagnetic field fluctuations at an Antarctic (Terra Nova Bay) and a low latitude (L'Aquila, Italy) station during the Earth's passage of a coronal ejecta on April 11, 1997 shows that major solar wind pressure variations were followed at both stations by a high fluctuation level. During northward interplanetary magnetic field conditions and when Terra Nova Bay is close to the local geomagnetic noon, coherent fluctuations, at the same frequency (3.6 mHz) and with polarization characteristics indicating an antisunward propagation, were observed simultaneously at the two stations. An analysis of simultaneous measurements from geosynchronous satellites shows evidence for pulsations at approximately the same frequencies also in the magnetospheric field. The observed waves might then be interpreted as oscillation modes, triggered by an external stimulation, extending to a major portion of the Earth's magnetosphere. Key words. Magnetospheric physics (MHD waves and instabilities; solar wind-magnetosphere interactions)

scholarly journals Rosetta and Mars Express observations of the influence of high solar wind pressure on the Martian plasma environment

2009 ◽  
Vol 27 (12) ◽  
pp. 4533-4545 ◽  
Author(s):  
N. J. T. Edberg ◽  
U. Auster ◽  
S. Barabash ◽  
A. Bößwetter ◽  
D. A. Brain ◽  
...  
Keyword(s):  
Magnetic Field ◽  
High Pressure ◽  
Solar Wind ◽  
Pressure Pulse ◽  
Wind Pressure ◽  
Data Set ◽  
Mars Express ◽  
Boundary Crossings ◽  
Plasma Environment ◽  
Solar Wind Pressure

Abstract. We report on new simultaneous in-situ observations at Mars from Rosetta and Mars Express (MEX) on how the Martian plasma environment is affected by high pressure solar wind. A significant sharp increase in solar wind density, magnetic field strength and turbulence followed by a gradual increase in solar wind velocity is observed during ~24 h in the combined data set from both spacecraft after Rosetta's closest approach to Mars on 25 February 2007. The bow shock and magnetic pileup boundary are coincidently observed by MEX to become asymmetric in their shapes. The fortunate orbit of MEX at this time allows a study of the inbound boundary crossings on one side of the planet and the outbound crossings on almost the opposite side, both very close to the terminator plane. The solar wind and interplanetary magnetic field (IMF) downstream of Mars are monitored through simultaneous measurements provided by Rosetta. Possible explanations for the asymmetries are discussed, such as crustal magnetic fields and IMF direction. In the same interval, during the high solar wind pressure pulse, MEX observations show an increased amount of escaping planetary ions from the polar region of Mars. We link the high pressure solar wind with the observed simultaneous ion outflow and discuss how the pressure pulse could also be associated with the observed boundary shape asymmetry.

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