Effects of continuous solar wind pressure variations on the long-lasting penetration of the interplanetary electric field during southward interplanetary magnetic field

2007 ◽  
Vol 39 (8) ◽  
pp. 1342-1346 ◽  
Author(s):  
Zhigang Yuan ◽  
Xiaohua Deng
1999 ◽  
Vol 104 (A9) ◽  
pp. 19923-19930 ◽  
Author(s):  
P. Francia ◽  
S. Lepidi ◽  
U. Villante ◽  
P. Di Giuseppe ◽  
A. J. Lazarus

2012 ◽  
Vol 90 (8) ◽  
pp. 753-758 ◽  
Author(s):  
D.J. McEwen ◽  
G.G. Sivjee

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.


2009 ◽  
Vol 27 (6) ◽  
pp. 2457-2474 ◽  
Author(s):  
C. Forsyth ◽  
M. Lester ◽  
R. C. Fear ◽  
E. Lucek ◽  
I. Dandouras ◽  
...  

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.


1971 ◽  
Vol 2 ◽  
pp. 173-188
Author(s):  
C. P. Sonett ◽  
P. Dyal ◽  
D. S. Colburn ◽  
B. F. Smith ◽  
G. Schubert ◽  
...  

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.


2009 ◽  
Vol 27 (12) ◽  
pp. 4533-4545 ◽  
Author(s):  
N. J. T. Edberg ◽  
U. Auster ◽  
S. Barabash ◽  
A. Bößwetter ◽  
D. A. Brain ◽  
...  

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.


1980 ◽  
Vol 58 (2) ◽  
pp. 255-269 ◽  
Author(s):  
Gordon Rostoker ◽  
R. P. Sharma

In the past decade there has developed a body of circumstantial evidence suggesting that terrestrial meteorology is influenced by plasma and magnetic field properties of the solar wind. In this paper we shall present evidence which strongly suggests that variations in surface pressure at high latitude stations ringing the Gulf of Alaska are correlated with changes in direction of the interplanetary magnetic field. We shall also present evidence that the changes in surface pressure may depend on whether the interplanetary magnetic field changes from pointing sunward to pointing antisunward or vice versa. We shall discuss the role that the magnetospheric electric field, which is heavily modulated by the interplanetary magnetic field, may play in influencing processes which lead to changes in terrestrial weather patterns.


2018 ◽  
Vol 36 (5) ◽  
pp. 1319-1333 ◽  
Author(s):  
Galina Korotova ◽  
David Sibeck ◽  
Scott Thaller ◽  
John Wygant ◽  
Harlan Spence ◽  
...  

Abstract. We employ multipoint observations of the Van Allen Probes, THEMIS, GOES and Cluster to present case and statistical studies of the electromagnetic field, plasma and particle response to interplanetary (IP) shocks observed by the Wind satellite. On 27 February 2014 the initial encounter of an IP shock with the magnetopause occurred on the postnoon magnetosphere, consistent with the observed alignment of the shock with the spiral IMF. The dayside equatorial magnetosphere exhibited a dusk–dawn oscillatory electrical field with a period of ∼330 s and peak-to-peak amplitudes of ∼15 mV m−1 for a period of 30 min. The intensity of electrons in the energy range from 31.5 to 342 KeV responded with periods corresponding to the shock-induced ULF (ultralow frequency) electric field waves. We then perform a statistical study of Ey variations of the electric field and associated plasma drift flow velocities for 60 magnetospheric events during the passage of interplanetary shocks. The Ey perturbations are negative (dusk-to-dawn) in the dayside magnetosphere (followed by positive or oscillatory perturbations) and dominantly positive (dawn-to-dusk direction) in the nightside magnetosphere, particularly near the Sun–Earth line within an L-shell range from 2.5 to 5. The typical observed amplitudes range from 0.2 to 6 mV m−1 but can reach 12 mV during strong magnetic storms. We show that electric field perturbations increase with solar wind pressure, and the changes are especially marked in the dayside magnetosphere. The direction of the Vx component of plasma flow is in agreement with the direction of the Ey component and is antisunward at all local times except the nightside magnetosphere, where it is sunward near the Sun–Earth line. The flow velocities Vx range from 0. 2 to 40 km s−1 and are a factor of 5 to 10 times stronger near noon as they correspond to greater variations of the electric field in this region. We demonstrate that the shock-induced electric field signatures can be classified into four different groups according to the initial Ey electric field response and these signatures are dependent on local time. Negative and bipolar pulses predominate on the dayside while positive pulses occur on the nightside. The ULF electric field pulsations of Pc and Pi types produced by IP shocks are observed at all local times and in the range of periods from several tens of seconds to several minutes. We believe that most electric field pulsations of the Pc5 type in the dayside magnetosphere at L<6 are produced by field line resonances. We show that the direction of the shock normal determines the direction of the propagation of the shock-induced magnetic and plasma disturbances. The observed directions of velocity Vy predominately agree with those expected for the given spiral or orthospiral shock normal orientation.


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