scholarly journals MLT dependence in the relationship between plasmapause, solar wind, and geomagnetic activity based on CRRES: 1990-1991

2016 ◽  
Vol 121 (5) ◽  
pp. 4397-4408 ◽  
Author(s):  
Mario Bandić ◽  
Giuli Verbanac ◽  
Mark B. Moldwin ◽  
Viviane Pierrard ◽  
Giovanni Piredda
Keyword(s):  
Solar Wind ◽  
Geomagnetic Activity ◽  
The Relationship

On the Relationship between Solar Wind Characteristics and Geomagnetic Activity

2009 ◽  
Author(s):  
C. Pirvutoiu ◽  
D. Vladoiu ◽  
G. Maris ◽  
Ivan Zhelyazkov
Keyword(s):  
Solar Wind ◽  
Geomagnetic Activity ◽  
Wind Characteristics ◽  
The Relationship

scholarly journals Evolution of fractality in magnetized plasmas

2017 ◽  
Author(s):  
Víctor Muñoz ◽  
Macarena Domínguez ◽  
Juan Alejandro Valdivia ◽  
Simon Good ◽  
Giuseppina Nigro ◽  
...  
Keyword(s):  
Solar Wind ◽  
Fractal Dimension ◽  
Shell Model ◽  
Geomagnetic Activity ◽  
Temporal Evolution ◽  
Fractal Dimensions ◽  
Magnetized Plasma ◽  
Magnetic Clouds ◽  
The Relationship ◽  
The Magnetic Field

Abstract. We studied the temporal evolution of fractality for geomagnetic activity, by calculating fractal dimensions from Dst data and from an MHD shell model for a turbulent magnetized plasma, which may be a useful model to study geomagnetic activity under solar wind forcing. We show that the shell model is able to reproduce the relationship between the fractal dimension and the occurrence of dissipative events, but only in a certain region of viscosity and resistivity values. We also present preliminary results of the application of these ideas to the study of the magnetic field time series in the solar wind during magnetic clouds. Results suggest that the fractal dimension is able to characterize the complexity of the magnetic cloud structure.

scholarly journals Evolution of fractality in space plasmas of interest to geomagnetic activity

2018 ◽  
Vol 25 (1) ◽  
pp. 207-216 ◽  
Author(s):  
Víctor Muñoz ◽  
Macarena Domínguez ◽  
Juan Alejandro Valdivia ◽  
Simon Good ◽  
Giuseppina Nigro ◽  
...  
Keyword(s):  
Solar Wind ◽  
Fractal Dimension ◽  
Shell Model ◽  
Geomagnetic Activity ◽  
Temporal Evolution ◽  
Fractal Dimensions ◽  
Magnetized Plasma ◽  
Magnetic Clouds ◽  
The Relationship ◽  
The Magnetic Field

Abstract. We studied the temporal evolution of fractality for geomagnetic activity, by calculating fractal dimensions from the Dst data and from a magnetohydrodynamic shell model for turbulent magnetized plasma, which may be a useful model to study geomagnetic activity under solar wind forcing. We show that the shell model is able to reproduce the relationship between the fractal dimension and the occurrence of dissipative events, but only in a certain region of viscosity and resistivity values. We also present preliminary results of the application of these ideas to the study of the magnetic field time series in the solar wind during magnetic clouds, which suggest that it is possible, by means of the fractal dimension, to characterize the complexity of the magnetic cloud structure.

ASSOCIATION BETWEEN VARIATIONS OF SOLAR WIND PARAMETERS AND GEOMAGNETIC ACTIVITY INDEX Ap IN 2003 - 2005

2011 ◽  
Vol 2 (3) ◽  
pp. 205-210 ◽  
Author(s):  
Igor Savel'evich Fal'kovich ◽  
M. R. Olyak ◽  
Nikolai Nikolaevich Kalinichenko ◽  
I. N. Bubnov
Keyword(s):  
Solar Wind ◽  
Geomagnetic Activity ◽  
Activity Index ◽  
Solar Wind Parameters ◽  
Geomagnetic Activity Index

scholarly journals Tests for coronal electron temperature signatures in suprathermal electron populations at 1 AU

2017 ◽  
Vol 35 (6) ◽  
pp. 1275-1291 ◽  
Author(s):  
Allan R. Macneil ◽  
Christopher J. Owen ◽  
Robert T. Wicks
Keyword(s):  
Solar Wind ◽  
Electron Temperature ◽  
Energy Content ◽  
The Sun ◽  
Particle Interactions ◽  
Core Electron ◽  
Suprathermal Electron ◽  
Electron Distributions ◽  
The Relationship ◽  
Coronal Electron

Abstract. The development of knowledge of how the coronal origin of the solar wind affects its in situ properties is one of the keys to understanding the relationship between the Sun and the heliosphere. In this paper, we analyse ACE/SWICS and WIND/3DP data spanning  > 12 years, and test properties of solar wind suprathermal electron distributions for the presence of signatures of the coronal temperature at their origin which may remain at 1 AU. In particular we re-examine a previous suggestion that these properties correlate with the oxygen charge state ratio O7+ ∕ O6+, an established proxy for coronal electron temperature. We find only a very weak but variable correlation between measures of suprathermal electron energy content and O7+ ∕ O6+. The weak nature of the correlation leads us to conclude, in contrast to earlier results, that an initial relationship with core electron temperature has the possibility to exist in the corona, but that in most cases no strong signatures remain in the suprathermal electron distributions at 1 AU. It cannot yet be confirmed whether this is due to the effects of coronal conditions on the establishment of this relationship or due to the altering of the electron distributions by processing during transport in the solar wind en route to 1 AU. Contrasting results for the halo and strahl population favours the latter interpretation. Confirmation of this will be possible using Solar Orbiter data (cruise and nominal mission phase) to test whether the weakness of the relationship persists over a range of heliocentric distances. If the correlation is found to strengthen when closer to the Sun, then this would indicate an initial relationship which is being degraded, perhaps by wave–particle interactions, en route to the observer.

scholarly journals Physical meaning of the equinoctial effect for semi-annual variation in geomagnetic activity

2009 ◽  
Vol 27 (5) ◽  
pp. 1909-1914 ◽  
Author(s):  
A. Yoshida
Keyword(s):  
Solar Wind ◽  
Wind Velocity ◽  
Geomagnetic Activity ◽  
Physical Meaning ◽  
Solar Wind Velocity ◽  
Annual Variation ◽  
Geomagnetic Disturbance ◽  
Data Sets ◽  
Key Factor ◽  
Solar Wind Parameters

Abstract. Physical meaning of the equinoctial effect for semi-annual variation in geomagnetic activity is investigated based on the three-hourly am index and solar wind parameters. When the z component of the interplanetary magnetic field (IMF) in geocentric solar magnetospheric (GSM) coordinates is southward, am indices are well correlated with BsVx2, where Bs is the southward component of the IMF and Vx is the solar wind velocity in the sun-earth direction. The am-BsVx2 relationship, however, depends on the range of Vx2: the am in higher ranges of Vx2 tends to be larger than am in lower ranges of Vx2 for the same value of BsVx2 for both equinoctial and solstitial epochs. Using the data sets of the same Vx2 range, it is shown that distribution of points in the am-BsVx2 diagram at the solstitial epochs overlaps with that at the equinoctial epochs and the average am values in each BsVx2 bin in solstitial epochs are closely consistent with those in equinoctial epochs, if Vx2 for each point at solstices are reduced to Vx2sin2 (Ψ) where Ψ is the geomagnetic colatitude of the sub-solar point. Further, it is shown that monthly averages of the am index in the long period is well correlated with the values of sin2(ψ) for the middle day of each month. These findings indicate that the factor that contributes to the generation of geomagnetic disturbance is not the velocity of the solar wind, but the component of the solar wind velocity perpendicular to the dipole axis of the geomagnetic field. The magnitude of the perpendicular velocity component varies semi-annually even if the solar wind velocity remains constant, which is considered to be the long-missed key factor causing the equinoctial effect.

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