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Coronal mass ejections (CMEs) are the major eruptive phenomena that cause various space weather effects. CMEs can be deflected by coronal holes (CH) away or towards the Sun-Earth line depending on their relative location, and also the high speed streams from CH can influence CME propagation. Coronal dimmings which are away or toward the CH may also cause CME deflection. The main aim of our study is to analyse the deflection/rotation of CMEs by tracking them in COR1 and COR2 field of view of STEREO onboard SECCHI with the help of 3D reconstruction Graduated cylindrical shell (GCS) model. We analyse 60 Earth-directed CMEs and their associated low coronal signatures observed in SDO/AIA. In addition, with the help of CATCH tool we study the nearby coronal hole parameters. Furthermore, we analyze the associated coronal dimmings by considering the movement of secondary dimmings towards or away the nearby CH. Out of 60 events, 31 events show deflection/rotation, as we track them from 1.76R☉ to 20.8R☉. A small fraction of (11%) events show deflection in longitude, and a significant fraction of events show deflection in latitude (38%) and rotation (40%). We discuss these results with respect to the vicinity and direction of coronal holes.

A large sample of active-region-targeted time-series images from the Solar Dynamics Observatory / Atmospheric Imaging Assembly, the AIA Active Region Patch database ("AARPs", Paper I: Dissauer et al 2022) is used to investigate whether parameters describing the coronal, transition region, and chromospheric emission can differentiate a region that will imminently produce a solar flare from one that will not. Parametrizations based on moment analysis of direct and running-difference images provide for physically-interpretable results from nonparametric discriminant analysis. Across four event definitions including both 24hr and 6hr validity periods, 160 image-based parameters capture the general state of the atmosphere, rapid brightness changes, and longer-term intensity evolution. We find top Brier Skill Scores in the 0.07--0.33 range, True Skill Statistics in the 0.68--0.82 range (both depending on event definition), and Receiver Operating Characteristic Skill Scores above 0.8. Total emission can perform notably as can steeply increasing or decreasing brightness, although mean brightness measures do not, demonstrating the well-known active-region-size/flare-productivity relation. Once a region is flare productive, the active-region coronal plasma appears to stay hot. The 94AA filter data provides the most parameters with discriminating power, with indications that it benefits from sampling multiple physical regimes. In particular, classification success using higher-order moments of running difference images indicate a propensity for flare-imminent regions to display short-lived small-scale brightening events. Parameters describing the evolution of the corona can provide flare-imminent indicators, but at no preference over "static" parameters. Finally, all parameters and NPDA-derived probabilities are available to the community for additional research., Astrophysical Journal, in press

On March 12, 2012, a Coronal Mass Ejection (CME) was released from the Sun with a speed of ~2000 km/s. The CME source region was surrounded by three different coronal holes (CHs), located to the East (negative polarity), South-West (positive polarity) and West (positive polarity). Its interplanetary counterpart (ICME) impacted Earth and was in-situ measured by the Advanced Composition Explorer (ACE) / Wind at L1 and the Solar TErrestrial RElations Observatory Ahead (STEREO)-A on March 15th. During this period, the angular separation between the two locations was greater than 100 degrees. Nevertheless, the in-situ measurements revealed almost identical profiles with clear markers of ICME signatures, which is evidence of one of the widest reported multi-spacecraft detection of an ICME, having STEREO-A crossing the west flank and Earth the east flank. Supra-thermal electrons show signatures of bidirectionality and isotropy/simple strahl as the ICME crosses the different spacecraft, providing information about the eroded parts of the ICME. Certain parts might have been eroded, possibly due to the interaction with the fast solar wind produced by the nearby CHs. We analysed the propagation of the ICME structure using remote-sensing observations from both STEREOs and Earth together with different in-situ instrumentation at ~1 au, and performed a comparison between the physical properties derived at multiple spacecraft. This study shows the importance of multi-spacecraft observations to understand the large-scale structures of ICMEs, their evolution and interaction, as well as their implications for the space-weather discipline.

Coronal dimmings are regions in the solar corona that represent a sudden decrease of the coronal EUV and SXR emission, which is interpreted as a density depletion caused by the evacuation of plasma due to the CME eruption. Distinct relations have been established between coronal dimming parameters (intensity, area, magnetic flux) and key characteristics (mass, speed) of the associated CMEs by combining coronal and coronagraphic observations from different viewpoints in the heliosphere (Dissauer et al. 2019, Chikunova et al. 2020).In this contribution, we study whether coronal dimmings can be used to indicate possible deflections of CMEs close to the Sun and to identify their propagation direction. We present a set of detailed case studies where, by using simultaneous observations from the SDO and STEREO satellites, we track both the evolution of the coronal dimmings and the CME properties with respect to their directions. Our findings suggest that the direction of growth of the coronal dimming region and the evolution of the dimming intensity are related to the initial direction of the CME and also reflect various changes in its evolution, indicating deflection and/or interaction with surrounding active regions. These findings are important in better constraining CME evolution and direction close to the Sun and its further connection toward interplanetary space.

We investigated the interaction of a coronal mass ejection (CME) and a coronal hole (CH) in its vicinity using remote-sensing and 1 AU in situ data. We used extreme-ultraviolet images and magnetograms to identify coronal structures and coronagraph images to analyze the early CME propagation. The Wind spacecraft and the Advanced Composition Explorer (ACE) provide plasma and magnetic field data of near-Earth interplanetary space. We applied various diagnostic tools to the images and to the time-series data. We find that the CME erupts under a streamer and causes the evacuation of material at its far end, which is observable as dimming and subsequent CH formation. The CME is likely deflected in its early propagation and travels southwest of the Sun-Earth line. In situ data lack signatures of a large magnetic cloud, but show a small flux rope at the trailing edge of the interplanetary CME (ICME), followed by an Alfvénic wave. This wave is identified as exhaust from a Petschek-type reconnection region following the successful application of a Walén test. We infer that the two spacecraft at 1 AU most likely traverse the ICME leg that is in the process of reconnection along the heliospheric current sheet that separates the ICME and the high-speed stream outflowing from the CH.