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

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)

Superposed Epoch Analysis of High Latitude Ionospheric Joule Heating during Major Geomagnetic Storms over three Solar Cycles

2018 ◽  
Vol 13 (S340) ◽  
pp. 67-68
Author(s):  
K. J. Suji ◽  
P. R. Prince
Keyword(s):  
Solar Wind ◽  
Joule Heating ◽  
High Latitude ◽  
Geomagnetic Storms ◽  
Dynamic Pressure ◽  
Basic Structure ◽  
Proton Density ◽  
Solar Cycles ◽  
Superposed Epoch Analysis ◽  
Epoch Analysis

AbstractSuperposed epoch analysis (SPEA) is commonly used to determine some basic structure in a collection of geophysical time series. The present study tries to analyze ionospheric Joule heating response at high latitudes, to the prevailing solar wind and IMF conditions on the basis of SPEA. Major geomagnetic storms (CME driven) over three consecutive solar cycles (SC 22, 23 and 24) have been selected. Ascending phase, solar maximum, and declining phase are investigated separately, for each solar cycle, to find out crucial controlling parameters for the generation of high-latitude ionospheric Joule heating. SPEA results show that, IMF parameters such as IMF By, IMF Bz, IMF clock angle and solar wind parameters such as dynamic pressure and proton density influence Joule heating production rate significantly. Meanwhile, the relentlessness of the other parameters such as IMFBt and solar wind bulk speed show that they have poor impact on Joule heating.

scholarly journals Solar wind conditions leading to efficient radiation belt electron acceleration: A superposed epoch analysis

2015 ◽  
Vol 42 (17) ◽  
pp. 6906-6915 ◽  
Author(s):  
W. Li ◽  
R. M. Thorne ◽  
J. Bortnik ◽  
D. N. Baker ◽  
G. D. Reeves ◽  
...  
Keyword(s):  
Solar Wind ◽  
Radiation Belt ◽  
Electron Acceleration ◽  
Superposed Epoch Analysis ◽  
Epoch Analysis
Sign in / Sign up

Export Citation Format

Share Document