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

Yermolaev, Yu. I.; Лодкина, И. Г.; Nikolaeva, N. S.; Yermolaev, M. Yu.

doi:10.1002/2015ja021274

Cited by 44 publications

(33 citation statements)

References 57 publications

(100 reference statements)

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“…The average value of the Mach number of the forward shocks (M ms (F) = 1.67) was less than the average value of the Mach number of the reverse shocks (M ms (R) = 1.76). Statistically, the properties of shocks (the ratio of downstream magnetic field intensity to upstream magnetic field intensity (B d ∕B u ), magnetosonic Mach number (M ms ), ratio of the plasma pressure to the magnetic pressure ( ), and the angle ( Bn ) between the IMF and the shock normal) were not a primordial agent in increasing the intensity of the GS but increases the probability of magnetospheric activity as mentioned in Yermolaev et al [2015]. We found a low correlation between the intensity of the GSs and the characteristics of the shocks.…”

Section: Resultsmentioning

confidence: 97%

Geoeffectiveness of stream interaction regions during 2007–2008

et al. 2017

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The stream interaction regions (SIRs) are generated in the interplanetary medium when a fast solar wind stream overtakes a slower one. If these large‐scale phenomena interact with the Earth's magnetosphere, they can give rise to geomagnetic storms (GSs). Their geoeffectivity is measured using magnetic indices at different latitudes. In this study we analyzed the geoeffectiveness of 20 GSs that were generated by SIRs during the period of 2007 to 2008 and observed by the ACE, Wind, and STEREO‐A/B spacecraft. We compared the geomagnetic response to the SIRs‐magnetosphere interaction employing different geomagnetic indices at low, middle, and high latitudes. The geoeffectiveness was 50%, 55%, and 90% using the criteria of the aa, Kp, and SYM‐H indices, respectively. We found that in most cases the maximum intensity of each index was in the weak to moderate range. According to the SYM‐H index, a 10%, 60%, and 10% of the forward shocks were followed by quiet, weak, and moderate GSs, respectively. The 10% and 20%, however, were followed by minor and moderate GSs, respectively, according to the Kp index. We analyzed the geoeffective region within the SIRs with respect to the relative position of the stream interface (SI). For 75% of GSs, their maximum intensity occurred during the disturbed fast solar wind (after the passing of the SI), which would be related to the efficiency of a SIR. The time difference Δt between the passing of the SI and the maximum intensity in each index was less than 36 h.

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Section: Resultsmentioning

confidence: 97%

Geoeffectiveness of stream interaction regions during 2007–2008

et al. 2017

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“…In present paper we use the same data and methods as in our previous works (Yermolaev et al, 2015; (1) the one hour (1-h) interplanetary plasma and magnetic field data of the OMNI database (http://omniweb.gsfc.nasa.gov (King and Papitashvili, 2004)), (2) our catalog of largescale solar-wind phenomena during 1976-2000 (ftp://ftp.iki.rssi.ru/pub/omni/ (Yermolaev et al, 2009)) and (3) the double superposed epoch analysis method (Yermolaev et al, 2010). This method involves re-scaling (proportional increasing/decreasing time between points) the duration of the interval for all SW types in such a manner that, respectively, beginnings and ends of all intervals of a selected type coincide.…”

Section: Methodsmentioning

confidence: 99%

Dynamics of Large-Scale Solar-Wind Streams Obtained by the Double Superposed Epoch Analysis: 3. Deflection of the Velocity Vector

2018

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This work is a continuation of our previous articles (Yermolaev et al. in J. Geophys.Res. 120, 7094, 2015; Yermolaev et al. in Solar Phys. 292, 193, 2017), which describe the average temporal profiles of interplanetary plasma and field parameters in large-scale solar-wind (SW) streams: corotating interaction regions (CIRs), interplanetary coronal mass ejections (ICMEs including both magnetic clouds (MCs) and ejecta), and sheath as well as interplanetary shocks (ISs). Changes of longitude angle φ in CIRs from -2 to +2° agree with earlier observations. Besides we have for the first time analyzed the average temporal profiles of bulk velocity angles in Sheaths and ICMEs and found that the angle φ in ICME changes from 2 to −2° while in Sheath it changes from −2 to 2° (similar to change in CIR), i.e., the streams in CIR/Sheath and ICME deflect in the opposite side. When averaging the latitude angle ϑ on all intervals of the chosen SW type, the angle ϑ is almost constant ~1°. We made selection of SW events with increasing and decreasing angle ϑ for the first time and found that average temporal profiles for angle ϑ in selected events have the same "integral-like" shape as for angle φ. The difference in average profiles for angles φ and ϑ is explained by the fact that most events have increasing profiles for angle in ecliptic plane due to solar rotation while for angle in meridional plane numbers of increasing and decreasing profiles are equal.

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“…Numerical criteria and procedure of identification are described in details by Yermolaev et al (2009), the catalog of the identified solar wind phenomena for 1976-2016 is presented at the web-site of Space Research Institute, Moscow (IKI solar wind database) 8 . By analysis of the data of the OMNI dataset 9 for the period 1976-2000 and using the method of the double superposed epoch analysis for large numbers of events (Yermolaev et al, 2010), we classified and parameterized temporal sequences of phenomena in assumption of absence of interaction with other streams (Yermolaev et al, 2015). As a result, the averaged temporal profiles for the main parameters of solar wind and IMF have been obtained.…”

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

Cited by 44 publications

References 57 publications

Geoeffectiveness of stream interaction regions during 2007–2008

Geoeffectiveness of stream interaction regions during 2007–2008

Dynamics of Large-Scale Solar-Wind Streams Obtained by the Double Superposed Epoch Analysis: 3. Deflection of the Velocity Vector

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

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