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Origins of Rolling, Twisting, and Non-radial Propagation of Eruptive Solar Events
Vourlidas, Angelos; Velli, Marco; Panasenco, Olga +1 more
We demonstrate that major asymmetries in erupting filaments and CMEs, namely major twists and non-radial motions are typically related to the larger-scale ambient environment around eruptive events. Our analysis of prominence eruptions observed by the STEREO, SDO, and SOHO spacecraft shows that prominence spines retain, during the initial phases, …
Stealth Coronal Mass Ejections: A Perspective
Howard, Timothy A.; Harrison, Richard A.
"Stealth CME" has become a commonly used term in recent studies of solar activity. It refers to a coronal mass ejection (CME) with no apparent solar surface association, and therefore has no easily identifiable signature to locate the region on the Sun from which the CME erupted. We review the literature and express caution in categorising CMEs in…
Three-Dimensional Evolution of Erupted Flux Ropes from the Sun (2 - 20 R ⊙) to 1 AU
Kilpua, E. K. J.; Vourlidas, A.; Isavnin, A.
Studying the evolution of magnetic clouds entrained in coronal mass ejections using in-situ data is a difficult task, since only a limited number of observational points is available at large heliocentric distances. Remote sensing observations can, however, provide important information for events close to the Sun. In this work we estimate the flu…
The SWAP EUV Imaging Telescope. Part II: In-flight Performance and Calibration
Mierla, M.; Berghmans, D.; Seaton, D. B. +6 more
The Sun Watcher with Active Pixel System detector and Image Processing (SWAP) telescope was launched on 2 November 2009 onboard the ESA PROBA2 technological mission and has acquired images of the solar corona every one to two minutes for more than two years. The most important technological developments included in SWAP are a radiation-resistant C…
Initiation of Coronal Mass Ejections by Sunspot Rotation
van Driel-Gesztelyi, L.; Temmer, M.; Veronig, A. M. +3 more
We study a filament eruption, two-ribbon flare, and coronal mass ejection (CME) that occurred in NOAA Active Region 10898 on 6 July 2006. The filament was located South of a strong sunspot that dominated the region. In the evolution leading up to the eruption, and for some time after it, a counter-clockwise rotation of the sunspot of about 30 degr…
The LYRA Instrument Onboard PROBA2: Description and In-Flight Performance
Schmutz, W.; Shapiro, A. I.; Zhukov, A. N. +7 more
The Large Yield Radiometer (LYRA) is an XUV-EUV-MUV (soft X-ray to mid-ultraviolet) solar radiometer onboard the European Space Agency Project for On-Board Autonomy 2 (PROBA2) mission, which was launched in November 2009. LYRA acquires solar-irradiance measurements at a high cadence (nominally 20 Hz) in four broad spectral channels, from soft X-ra…
Ensemble Modeling of CME Propagation
Arge, C. N.; Henney, C. J.; Pizzo, V. +4 more
The current progression toward solar maximum provides a unique opportunity to use multi-perspective spacecraft observations together with numerical models to better understand the evolution and propagation of coronal mass ejections (CMEs). Of interest to both the scientific and forecasting communities are the Earth-directed "halo" CMEs, since they…
Coronal Hole Influence on the Observed Structure of Interplanetary CMEs
Gopalswamy, N.; Yashiro, S.; Mäkelä, P. +3 more
We report on the coronal hole (CH) influence on the 54 magnetic cloud (MC) and non-MC associated coronal mass ejections (CMEs) selected for studies during the Coordinated Data Analysis Workshops (CDAWs) focusing on the question if all CMEs are flux ropes. All selected CMEs originated from source regions located between longitudes 15E - 15W. Xie, G…
The Solar Connection of Enhanced Heavy Ion Charge States in the Interplanetary Medium: Implications for the Flux-Rope Structure of CMEs
Gopalswamy, N.; Yashiro, S.; Mäkelä, P. +3 more
We investigated a set of 54 interplanetary coronal mass ejection (ICME) events whose solar sources are very close to the disk center (within ± 15∘ from the central meridian). The ICMEs consisted of 23 magnetic-cloud (MC) events and 31 non-MC events. Our analyses suggest that the MC and non-MC ICMEs have more or less the same eruption ch…
PROBA2: Mission and Spacecraft Overview
Zender, J.; Schwehm, G.; de Groof, A. +9 more
Within the European Space Agency's (ESA) General Support and Technology Programme (GSTP), the Project for On-Board Autonomy (PROBA) missions provide a platform for in-orbit technology demonstration. Besides the technology demonstration goal, the satellites allow to provide services to, e.g., scientific communities. PROBA1 has been providing multi-…