Abstract
In a thorough study, we investigate the origin of a remarkable plasma and magnetic field configuration observed in situ on June 22, 2011, near L1, which appears to be a magnetic ejecta (ME) and a shock signature engulfed by a solar wind high-speed stream (HSS). We identify the signatures as an Earth-directed coronal mass ejection (CME), associated with a C7.7 flare on June 21, 2011, and its interaction with a HSS, which emanates from a coronal hole (CH) close to the launch site of the CME. The results indicate that the major interaction between the CME and the HSS starts at a height of 1.3~mbox{R}_{odot } up to 3~mbox{R}_{odot }. Over that distance range, the CME undergoes a strong north-eastward deflection of at least 30^{circ } due to the open magnetic field configuration of the CH. We perform a comprehensive analysis for the CME–HSS event using multi-viewpoint data (from the Solar TErrestrial RElations Observatories, the Solar and Heliospheric Observatory and the Solar Dynamics Observatory), and combined modeling efforts (nonlinear force-free field modeling, Graduated Cylindrical Shell CME modeling, and the Forecasting a CME’s Altered Trajectory – ForeCAT model). We aim at better understanding its early evolution and interaction process as well as its interplanetary propagation and related in situ signatures, and finally the resulting impact on the Earth’s magnetosphere.
Highlights
Coronal mass ejections (CME) frequently pass over Earth at an average rate of 1 – 2 events per month but with significant variations throughout the solar cycle (Richardson and Cane, 2010)
We present a detailed case study of a CME ejected on June 21, 2011, using multi-viewpoint remote sensing and in situ observations supported by modeling to better understand and explain the intriguing in situ solar wind signatures observed as a consequence of the CME interacting with a nearby coronal hole (CH)
We studied the origin of a peculiar in situ signature measured at 1 AU, caused by an Earthdirected ICME and its interaction with a nearby high speed streams (HSS) with the aim to address two major questions: How such a unique in situ signature could be formed and whether the observed shock was still driven
Summary
Coronal mass ejections (CME) frequently pass over Earth at an average rate of 1 – 2 events per month but with significant variations throughout the solar cycle (Richardson and Cane, 2010). It is understood that changes in CME properties differ strongly for processes taking place already low in the corona compared to those happening in interplanetary space (Wang et al, 2014b; Winslow et al, 2016) All these effects alter the initial CME properties observed close to the Sun making predictions of arrival time and geoeffectiveness a complex endeavor (Richardson, 2018). This shows that the ambient solar wind plays an important role for CME propagation, and that it is necessary to study and understand the interaction processes already from its source on the Sun and related 1 AU signatures
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
