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

Abstract

-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

Properties and Geoeffectiveness of Solar Wind High‐Speed Streams and Stream Interaction Regions During Solar Cycles 23 and 24

“…This issue is not severe during solar minimum years, but becomes important during solar maximum years. One must also keep in mind that some of the rejected events may be real SIR/HSS events that are interacting with a simultaneously occurring ICME event near the ecliptic plane [see, e.g., Al-Shakarchi and Morgan, 2018;Shugay et al, 2018].…”

Formation of Coronal Mass Ejection and Posteruption Flow of Solar Wind on 2010 August 18 Event

“…A statistical study of Temmer et al (2017) in the time period 2011-2015 has shown that CMEs often are followed by a trailing region behind their rear that has declining speed and a duration up to several days, which is much longer than the average CME duration itself (about 1.3 days). As a result, powerful CMEs can cause disturbances of the interplanetary medium, which may lead to significant deviations in the CME arrival times and speeds from those initially predicted, especially in the case of slow CMEs (Möstl et al 2014;Corona-Romero et al 2017;Shugay et al 2018;Ravishankar & Michałek 2019).…”

Formation of Coronal Mass Ejection and Post-eruption Flow of Solar Wind on 2010 August 18 event

“…A statistical study of Temmer et al (2017) in the time period 2011 -2015 has shown that CMEs often are followed by a trailing region behind its rear with declining speed with duration up to several days which much longer than the average CME duration itself (about 1.3 days). As a result, powerful CMEs can cause disturbances of the interplanetary medium, which may led to significant deviations of the CME arrival times and speeds from the initially predicted, especially, in the case of slow CMEs (Möstl et al 2014;Corona-Romero et al 2017;Shugay et al 2018;Ravishankar & Micha lek 2019).…”