scholarly journals Low-latitude ionospheric electric and magnetic field disturbances in response to solar wind pressure enhancements

2008 ◽  
Vol 113 (A8) ◽  
pp. n/a-n/a ◽  
Author(s):  
Chao-Song Huang ◽  
Kiyohumi Yumoto ◽  
Shuji Abe ◽  
George Sofko
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Wind Pressure ◽  
Low Latitude ◽  
Electric And Magnetic Field ◽  
Solar Wind Pressure

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 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.

Characteristics and variability of Titan's magnetic environment

2008 ◽  
Vol 367 (1889) ◽  
pp. 789-798 ◽  
Author(s):  
César L Bertucci
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Current Sheet ◽  
Radial Component ◽  
Wind Pressure ◽  
Rotation Direction ◽  
Background Magnetic Field ◽  
Solar Wind Pressure ◽  
Field Lines ◽  
The Magnetic Field

The structure and variability of Saturn's magnetic field in the vicinity of Titan's orbit is studied. In the dawn magnetosphere, the magnetic field presents a significant radial component directed towards Saturn, suggesting that Titan is usually located below the planet's warped and dynamic magnetodisc. Also, a non-negligible component along the co-rotation direction suggests that Saturn's magnetic field lines close to the magnetodisc are being swept back from their respective magnetic meridians. In the noon sector, Titan seems to be closer to the magnetodisc central current sheet, as the field lines in this region seem to be more dipolar. The distance between the central current sheet and Titan depends mainly on the solar wind pressure. Also, δ | B |/| B |∼0.5 amplitude waveforms at periods close to Saturn's kilometric radiation period are present in the background magnetic field. This modulation in the field is ubiquitous in Saturn's magnetosphere and associated with the presence of a rotating asymmetry in the planet's magnetic field.

scholarly journals Pc5 geomagnetic field fluctuations at discrete frequencies at a low latitude station

2001 ◽  
Vol 19 (3) ◽  
pp. 321-325 ◽  
Author(s):  
U. Villante ◽  
P. Francia ◽  
S. Lepidi
Keyword(s):  
Solar Wind ◽  
Geomagnetic Field ◽  
Wind Pressure ◽  
Mhd Waves ◽  
Low Latitude ◽  
Time Intervals ◽  
Latitude Station ◽  
Field Fluctuations ◽  
Mhd Waves And Instabilities ◽  
Solar Wind Pressure

Abstract. A statistical analysis of the geomagnetic field fluctuations in the Pc5 frequency range (1–5 mHz) at a low latitude station (L = 1.6) provides further evidence for daytime power peaks at discrete frequencies. The power enhancements, which become more pronounced during high solar wind pressure conditions, may be interpreted in terms of ground signatures of magnetospheric cavity/waveguide compressional modes driven by solar wind pressure pulses. In this sense, the much clearer statistical evidence for afternoon events can be related to corotating structures mainly impinging the postnoon magnetopause. A comparison with results obtained for the same time intervals from previous investigations at higher latitudes and in the Earth’s magnetosphere confirms the global character of the observed modes.Key words. Magnetospheric physics (MHD waves and instabilities; solar wind-magnetospheric interactions)

scholarly journals Even moderate geomagnetic pulsations can cause fluctuations of <i>fo</i>F2 frequency of the auroral ionosphere

2021 ◽  
Vol 39 (3) ◽  
pp. 549-562
Author(s):  
Nadezda Yagova ◽  
Alexander Kozlovsky ◽  
Evgeny Fedorov ◽  
Olga Kozyreva
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Critical Frequency ◽  
Solar Wind Speed ◽  
Weather Conditions ◽  
Wind Pressure ◽  
Geomagnetic Pulsations ◽  
Radio Waves ◽  
Magnetic Pulsations ◽  
Solar Wind Pressure

Abstract. The ionosonde at the Sodankylä Geophysical Observatory (SOD; 67∘ N, 27∘ E; Finland) routinely performs vertical sounding once per minute which enables the study of fast ionospheric variations at a frequency of the long-period geomagnetic pulsations Pc5–6/Pi3 (1–5 mHz). Using the ionosonde data from April 2014–December 2015 and colocated geomagnetic measurements, we have investigated a correspondence between the magnetic field pulsations and variations of the critical frequency of radio waves reflected from the ionospheric F2 layer (foF2). For this study, we have developed a technique for automated retrieval of the critical frequency of the F2 layer from ionograms. As a rule, the Pc5–6/Pi3 frequency band fluctuations in foF2 were observed at daytime during quiet or moderately disturbed space weather conditions. In most cases (about 80 %), the coherence between the foF2 variations and geomagnetic pulsations was low. However in some cases (specified as “coherent”) the coherence was as large as γ2≥0.5. The following conditions are favorable for the occurrence of coherent cases: enhanced auroral activity (6 h maximal auroral electrojet (AE) ≥800 nT), high solar wind speed (V>600 km/s), fluctuating solar wind pressure and northward interplanetary magnetic field. In the cases when the coherence was higher at shorter periods of oscillations, the magnetic pulsations demonstrated features typical for the Alfvén field line resonance.

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