Statistical Study of ICMEs and Their Sheaths During Solar Cycle 23 (1996 – 2008)

Mitsakou, E.; Moussas, X.

doi:10.1007/s11207-014-0505-y

Cited by 33 publications

(41 citation statements)

References 37 publications

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“…Obtained results on average values and temporal profiles of parameters in ICME (both Ejecta and MC) are in good agreement with earlier published results [Zurbuchen and Richardson, 2006;Richardson and Cane, 2012;Mitsakou and Moussas, 2014]. In addition to previous data we consider separately ICME with Sheath and IS and ICME without them.…”

Section: Discussionsupporting

confidence: 89%

“…Because of further selection on adjacent SW types, the subsets of events have lower statistics, the smallest statistics (nine events) was for MC without Sheath and IS (see Figure 6), and in other cases the subsets included from 18 to 372 events. As each type has characteristic (average) duration (see, e.g., Jian et al [2008], Yermolaev et al [2009], Mitsakou and Moussas [2014], and references therein), and duration of separate events can differ from average, the most effective way of studying of dynamics of parameters is the method of double superposed epoch analysis (DSEA) . We used various fixed durations for various types of streams which are close to average durations of corresponding SW types: 20 h for CIR, 25 h for Ejecta and MC, 14 h for Sheath before Ejecta, and 10 h for Sheath before MC.…”

Section: Methodsmentioning

confidence: 99%

“…In the mentioned above works the SW types are considered as sources of magnetospheric disturbance, i.e., the selection of SW events is carried out in connection with magnetospheric activity. There is only a small number of articles in which authors investigate the disturbed types of SW streams without their relation with the magnetospheric activity (see, e.g., papers by Zurbuchen and Richardson [2006], Yermolaev et al [2009], Borovsky and Denton [2010]; Thatcher and Müller [2011], Richardson and Cane [2012], Mitsakou and Moussas [2014], and Wu and Lepping [2015]). To understand geoeffectiveness of various types of SW streams, it is necessary to compare the characteristics of the streams inducing magnetic storm with the characteristics of all events of this type independently of possibility to storm generation.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2015

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Using the OMNI data for period 1976-2000 we investigate the temporal profiles of 20 plasma and field parameters in the disturbed large-scale types of solar wind (SW): CIR, ICME (both MC and Ejecta) and Sheath as well as the interplanetary shock (IS). To take into account the different durations of SW types we use the double superposed epoch analysis (DSEA) method: re-scaling the duration of the interval for all types in such a manner that, respectively, beginning and end for all intervals of selected type coincide. As the analyzed SW types can interact with each other and change parameters as a result of such interaction, we investigate separately 8 sequences of SW types: (1) CIR, (2) IS/CIR, (3) Ejecta, (4) Sheath/Ejecta, (5) IS/Sheath/Ejecta, (6) MC, (7) Sheath/MC, and ( 8) IS/Sheath/MC. The main conclusion is that the behavior of parameters in Sheath and in CIR are very similar both qualitatively and quantitatively. Both the high-speed stream (HSS) and the fast ICME play a role of pistons which push the plasma located ahead them. The increase of speed in HSS and ICME leads at first to formation of compression regions (CIR and Sheath, respectively), and then to IS. The occurrence of compression regions and IS increases the probability of growth of magnetospheric activity.

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Section: Discussionsupporting

confidence: 89%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

et al. 2015

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“…Indeed, in the central part of MCs, the observables are distributed in a log-normal manner (Rodriguez et al 2016). Similar log-normal distributions also have been found for ICME observables in Guo et al (2010) and Mitsakou & Moussas (2014).…”

Section: Methodssupporting

confidence: 74%

Superposed epoch study of ICME sub-structures near Earth and their effects on Galactic cosmic rays

Masías-Meza

Dasso

Démoulin

et al. 2016

A&A

113

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Context. Interplanetary coronal mass ejections (ICMEs) are the interplanetary manifestations of solar eruptions. The overtaken solar wind forms a sheath of compressed plasma at the front of ICMEs. Magnetic clouds (MCs) are a subset of ICMEs with specific properties (e.g. the presence of a flux rope). When ICMEs pass near Earth, ground observations indicate that the flux of Galactic cosmic rays (GCRs) decreases. Aims. The main aims of this paper are to find common plasma and magnetic properties of different ICME sub-structures and which ICME properties affect the flux of GCRs near Earth. Methods. We used a superposed epoch method applied to a large set of ICMEs observed in situ by the spacecraft ACE, between 1998 and 2006. We also applied a superposed epoch analysis on GCRs time series observed with the McMurdo neutron monitors. Results. We find that slow MCs at 1 AU have on average more massive sheaths. We conclude that this is because they are more effectively slowed down by drag during their travel from the Sun. Slow MCs also have a more symmetric magnetic field and sheaths expanding similarly as their following MC, while in contrast, fast MCs have an asymmetric magnetic profile and a sheath in compression. In all types of MCs, we find that the proton density and the temperature and the magnetic fluctuations can diffuse within the front of the MC due to 3D reconnection. Finally, we derive a quantitative model that describes the decrease in cosmic rays as a function of the amount of magnetic fluctuations and field strength. Conclusions. The obtained typical profiles of sheath, MC and GCR properties corresponding to slow, middle, and fast ICMEs, can be used for forecasting or modelling these events, and to better understand the transport of energetic particles in ICMEs. They are also useful for improving future operative space weather activities.

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“…Solar wind phenomena are typically identified using the standard criteria for the solar wind parameters (Sheeley & Harvey, 1981;Burlaga, 1991;Lepping et al, 2003;Zurbuchen & Richardson, 2006;Yermolaev et al, 2009;Borovsky & Denton, 2010;Mitsakou & Moussas, 2014;Prise et al, 2015). The solar wind features observed in connection with the HSS propagation are CIRs and HSSs (body): CIR is an interaction region between the slow and fast solar wind streams and characterized by an increase and then a decrease in the proton density, an increase in the velocity and kinetic temperature of the protons, an increase in the strength of the interplanetary magnetic field; HSS has the bulk speed V > 450 km s À1 (in the rise of Cycle 24 V > 400 km s À1 , Rod'kin et al, 2016) and low values of the proton density and magnetic field.…”

Section: Identification Of the Solar Wind Phenomena In-situmentioning

confidence: 99%

Influence of coronal mass ejections on parameters of high-speed solar wind: a case study

Shugay

Slemzin

Rodkin

et al. 2018

J. Space Weather Space Clim.

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-We investigate the case of disagreement between predicted and observed in-situ parameters of the recurrent high-speed solar wind streams (HSSs) existing for Carrington rotation (CR) 2118 (December 2011) in comparison with CRs 2117 and 2119. The HSSs originated at the Sun from a recurrent polar coronal hole (CH) expanding to mid-latitudes, and its area in the central part of the solar disk increased with the rotation number. This part of the CH was responsible for the equatorial flank of the HSS directed to the Earth. The time and speed of arrival for this part of the HSS to the Earth were predicted by the hierarchical empirical model based on EUV-imaging and the Wang-Sheeley-Arge ENLIL semi-empirical model. The predicted parameters were compared with those measured in-situ. It was found, that for CR 2117 and CR 2119, the predicted HSS speed values agreed with the measured ones within the typical accuracy of ±100 km s À1 . During CR 2118, the measured speed was on 217 km s À1 less than the value predicted in accordance with the increased area of the CH. We suppose that at CR 2118, the HSS overtook and interacted with complex ejecta formed from three merged coronal mass ejections (CMEs) with a mean speed about 400 km s À1 . According to simulations of the Drag-based model, this complex ejecta might be created by several CMEs starting from the Sun in the period between 25 and 27 December 2011 and arriving to the Earth simultaneously with the HSS. Due to its higher density and magnetic field strength, the complex ejecta became an obstacle

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Statistical Study of ICMEs and Their Sheaths During Solar Cycle 23 (1996 – 2008)

Cited by 33 publications

References 37 publications

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

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

Superposed epoch study of ICME sub-structures near Earth and their effects on Galactic cosmic rays

Influence of coronal mass ejections on parameters of high-speed solar wind: a case study

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