scholarly journals Energy Inflow into the Magnetosphere and Its Distribution During Magnetic Storm

2021 ◽  
Vol 12 (4) ◽  
Author(s):  
Vitalii Degtyarev ◽  
George Popov ◽  
Svetlana Chudnenko
Keyword(s):  
Solar Wind ◽  
Magnetic Storm ◽  
Anomalous Behavior ◽  
Magnetic Storms ◽  
Auroral Ionosphere ◽  
Analysis Method ◽  
Superposed Epoch Analysis ◽  
Circular Current ◽  
The Mean ◽  
Epoch Analysis

The energy inflow from the solar wind into the magnetosphere and its dissipation in the circular current and auroral ionosphere during maximums of magnetic storm intensity are considered. All magnetic storms with Dst intensities from –18 nT to –422 nT for the period from 1996 to 2014 were divided into groups. For each group, the mean contribution of energy from the solar wind to the magnetosphere and subsequent characteristics of the energy dissipation in the auroral ionosphere and circular current were determined by the superposed epoch analysis method. The nonlinearity of the dependence of the intensity of magnetic storms on the energy coming from the solar wind into the magnetosphere was revealed. Anomalous behavior of magnetic storms with intensity |Dst| > 200 nT was detected. A discussion of the results is given.

scholarly journals Specific interplanetary conditions for CIR-, Sheath-, and ICME-induced geomagnetic storms obtained by double superposed epoch analysis

2010 ◽  
Vol 28 (12) ◽  
pp. 2177-2186 ◽  
Author(s):  
Yu. I. Yermolaev ◽  
N. S. Nikolaeva ◽  
I. G. Lodkina ◽  
M. Yu. Yermolaev
Keyword(s):  
Large Scale ◽  
Geomagnetic Storms ◽  
Magnetic Cloud ◽  
Magnetic Storms ◽  
Main Phase ◽  
Corotating Interaction Region ◽  
Superposed Epoch Analysis ◽  
Epoch Analysis ◽  
Archive Data ◽  
Scale Types

Abstract. A comparison of specific interplanetary conditions for 798 magnetic storms with Dst <−50 nT during 1976–2000 was made on the basis of the OMNI archive data. We categorized various large-scale types of solar wind as interplanetary drivers of storms: corotating interaction region (CIR), Sheath, interplanetary CME (ICME) including both magnetic cloud (MC) and Ejecta, separately MC and Ejecta, and "Indeterminate" type. The data processing was carried out by the method of double superposed epoch analysis which uses two reference times (onset of storm and minimum of Dst index) and makes a re-scaling of the main phase of the storm in a such way that all storms have equal durations of the main phase in the new time reference frame. This method reproduced some well-known results and allowed us to obtain some new results. Specifically, obtained results demonstrate that (1) in accordance with "output/input" criteria the highest efficiency in generation of magnetic storms is observed for Sheath and the lowest one for MC, and (2) there are significant differences in the properties of MC and Ejecta and in their efficiencies.

scholarly journals Extremely intense (SML ≤–2500 nT) substorms: isolated events that are externally triggered?

2015 ◽  
Vol 33 (5) ◽  
pp. 519-524 ◽  
Author(s):  
B. T. Tsurutani ◽  
R. Hajra ◽  
E. Echer ◽  
J. W. Gjerloev
Keyword(s):  
Solar Wind ◽  
Magnetic Fields ◽  
Magnetic Storm ◽  
Solar Wind Plasma ◽  
Magnetic Storms ◽  
Input Energy ◽  
Stored Energy ◽  
Ionospheric Currents ◽  
Interplanetary Magnetic Fields ◽  
Very High

Abstract. We examine particularly intense substorms (SML &amp;leq;–2500 nT), hereafter called "supersubstorms" or SSS events, to identify their nature and their magnetic storm dependences. It is found that these intense substorms are typically isolated events and are only loosely related to magnetic storms. SSS events can occur during super (Dst &amp;leq;–250 nT) and intense (−100 nT &amp;geq; Dst >–250) magnetic storms. SSS events can also occur during nonstorm (Dst &amp;geq;–50 nT) intervals. SSSs are important because the strongest ionospheric currents will flow during these events, potentially causing power outages on Earth. Several SSS examples are shown. SSS events appear to be externally triggered by small regions of very high density (~30 to 50 cm−3) solar wind plasma parcels (PPs) impinging upon the magnetosphere. Precursor southward interplanetary magnetic fields are detected prior to the PPs hitting the magnetosphere. Our hypothesis is that these southward fields input energy into the magnetosphere/magnetotail and the PPs trigger the release of the stored energy.

scholarly journals The ionospheric heating beneath the magnetospheric cleft revisited

2005 ◽  
Vol 23 (3) ◽  
pp. 827-830 ◽  
Author(s):  
G. W. Prölss
Keyword(s):  
Magnetic Activity ◽  
Topside Ionosphere ◽  
Ionospheric Heating ◽  
Superposed Epoch Analysis ◽  
Theoretical Predictions ◽  
Northern Winter ◽  
The Mean ◽  
Epoch Analysis ◽  
Winter Hemisphere ◽  
Prominent Peak

Abstract. A prominent peak in the electron temperature of the topside ionosphere is observed beneath the magnetospheric cleft. The present study uses DE-2 data obtained in the Northern Winter Hemisphere to investigate this phenomenon. First, the dependence of the location and magnitude of the temperature peak on the magnetic activity is determined. Next, using a superposed epoch analysis, the mean latitudinal profile of the temperature enhancement is derived. The results of the present study are compared primarily with those obtained by Titheridge (1976), but also with more recent observations and theoretical predictions.

scholarly journals Different magnetospheric modes: solar wind driving and coupling efficiency

2009 ◽  
Vol 27 (11) ◽  
pp. 4281-4291 ◽  
Author(s):  
N. Partamies ◽  
T. I. Pulkkinen ◽  
R. L. McPherron ◽  
K. McWilliams ◽  
C. R. Bryant ◽  
...  
Keyword(s):  
Solar Wind ◽  
Solar Wind Speed ◽  
Coupling Efficiency ◽  
Slow Solar Wind ◽  
Cycle Phase ◽  
Particle Injection ◽  
Superposed Epoch Analysis ◽  
Magnetospheric Convection ◽  
Epoch Analysis ◽  
Steady Convection

Abstract. This study describes a systematic statistical comparison of isolated non-storm substorms, steady magnetospheric convection (SMC) intervals and sawtooth events. The number of events is approximately the same in each group and the data are taken from about the same years to avoid biasing by different solar cycle phase. The very same superposed epoch analysis is performed for each event group to show the characteristics of ground-based indices (AL, PCN, PC potential), particle injection at the geostationary orbit and the solar wind and IMF parameters. We show that the monthly occurrence of sawtooth events and isolated non-stormtime substorms closely follows maxima of the geomagnetic activity at (or close to) the equinoxes. The most strongly solar wind driven event type, sawtooth events, is the least efficient in coupling the solar wind energy to the auroral ionosphere, while SMC periods are associated with the highest coupling ratio (AL/EY). Furthermore, solar wind speed seems to play a key role in determining the type of activity in the magnetosphere. Slow solar wind is capable of maintaining steady convection. During fast solar wind streams the magnetosphere responds with loading–unloading cycles, represented by substorms during moderately active conditions and sawtooth events (or other storm-time activations) during geomagnetically active conditions.

scholarly journals Dynamics of large‐scale solar wind streams obtained by the double superposed epoch analysis

2015 ◽  
Vol 120 (9) ◽  
pp. 7094-7106 ◽  
Author(s):  
Yu. I. Yermolaev ◽  
I. G. Lodkina ◽  
N. S. Nikolaeva ◽  
M. Yu. Yermolaev
Keyword(s):  
Solar Wind ◽  
Large Scale ◽  
Superposed Epoch Analysis ◽  
Epoch Analysis

scholarly journals Superposed epoch analysis applied to large-amplitude travelling convection vortices

1998 ◽  
Vol 16 (7) ◽  
pp. 743-753 ◽  
Author(s):  
H. Lühr ◽  
M. Rother ◽  
T. Iyemori ◽  
T. L. Hansen ◽  
R. P. Lepping
Keyword(s):  
Solar Wind ◽  
Large Amplitude ◽  
Selection Criteria ◽  
Solar Rotation ◽  
Current System ◽  
Azimuthal Direction ◽  
Superposed Epoch Analysis ◽  
Northern Half ◽  
Epoch Analysis ◽  
Image Network

Abstract. For the six months from 1 October 1993 to 1 April 1994 the recordings of the IMAGE magnetometer network have been surveyed in a search for large-amplitude travelling convection vortices (TCVs). The restriction to large amplitudes (>100 nT) was chosen to ensure a proper detection of evens also during times of high activity. Readings of all stations of the northern half of the IMAGE network were employed to check the consistency of the ground signature with the notation of a dual-vortex structure moving in an azimuthal direction. Applying these stringent selection criteria we detected a total of 19 clear TCV events. The statistical properties of our selection resemble the expected characteristics of large-amplitude TCVs. New and unexpected results emerged from the superposed epoch analysis. TCVs tend to form during quiet intervals embedded in moderately active periods. The occurrence of events is not randomly distributed but rather shows a clustering around a few days. These clusters recur once or twice every 27 days. Within a storm cycle they show up five to seven days after the commencement. With regard to solar wind conditions, we see the events occurring in the middle of the IMF sector structure. Large-amplitude TCVs seem to require certain conditions to make solar wind transients 'geoeffective', which have the tendency to recur with the solar rotation period.Key words. Ionosphere (Aural ionosphere; Ionosphere- magnetosphere interactions) · Magnetospheric Physics (current system)

Temporal evolutions of the solar wind conditions at 1 AU prior to the near‐Earth X lines in the tail: Superposed epoch analysis

2016 ◽  
Vol 121 (8) ◽  
pp. 7488-7496 ◽  
Author(s):  
L. Q. Zhang ◽  
L. Dai ◽  
W. Baumjohann ◽  
A. T. Y. Lui ◽  
C. Wang ◽  
...  
Keyword(s):  
Solar Wind ◽  
Superposed Epoch Analysis ◽  
Epoch Analysis
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