Search Publications
Mysteries of the 17 May 2012 Solar Event Responsible for GLE71. I. CME Development and the Role of Disturbances Excited by Eruptions
Firoz, K. A.; Grechnev, V. V.; Lysenko, A. L. +3 more
The SOL2012-05-17 event is remarkable in that it caused one of two ground-level enhancements (GLE71) in Solar Cycle 24. Despite the efforts spent studying this solar event, some aspects of it remain unclear. This relates to the development of a coronal mass ejection (CME), the history of the shock wave, and the flare. Our measurements reveal the f…
On the Instrumental Discrepancies in Lyman-Alpha Observations of Solar Flares
Dammasch, Ingolf E.; Milligan, Ryan O.; Greatorex, Harry J.
Despite the energetic significance of Lyman-alpha (Ly
Localization of the Gamma-Ray Emission Region in the 1 September 2014 Behind-the-Limb Solar Flare According to the Fermi/LAT Data
Grechnev, V. V.; Kochanov, A. A.; Kiselev, V. I. +1 more
Since the launch of the Fermi mission in 2008, it has become possible to study high-energy solar γ-rays with an unprecedented imaging capability. In particular, the position of the >100 MeVγ-ray source can shed light on the origin of high-energy protons that is still controversial. However, the imaging of solar γ-ray sources with the Fermi Larg…
Defining the Middle Corona
Giordano, Silvio; Andretta, Vincenzo; Reeves, Katharine K. +39 more
The middle corona, the region roughly spanning heliocentric distances from 1.5 to 6 solar radii, encompasses almost all of the influential physical transitions and processes that govern the behavior of coronal outflow into the heliosphere. The solar wind, eruptions, and flows pass through the region, and they are shaped by it. Importantly, the reg…
Rapid Rotation of an Erupting Prominence and the Associated Coronal Mass Ejection on 13 May 2013
Zhang, Qingmin; Ji, Haisheng; Zhou, Yuhao
In this paper, we report the multiwavelength observations of an erupting prominence and the associated coronal mass ejection (CME) on 13 May 2013. The event occurs behind the western limb in the field of view of the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO) spacecraft. The prominence is supported by a highly …
The SWAP Filter: A Simple Azimuthally Varying Radial Filter for Wide-Field EUV Solar Images
Berghmans, David; Rachmeler, Laurel A.; West, Matthew J. +5 more
We present the SWAP Filter: an azimuthally varying, radial normalizing filter specifically developed for EUV images of the solar corona, named for the Sun Watcher with Active Pixels and Image Processing (SWAP) instrument on the Project for On-Board Autonomy 2 (PROBA2) spacecraft. We discuss the origins of our technique, its implementation and key …
Exploring the Circular Polarisation of Low-Frequency Solar Radio Bursts with LOFAR
Kumari, Anshu; Zucca, Pietro; Vocks, Christian +9 more
The Sun is an active star that often produces numerous bursts of electromagnetic radiation at radio wavelengths. Low frequency radio bursts have recently been brought back to light with the advancement of novel radio interferometers. However, their polarisation properties have not yet been explored in detail, especially with the Low Frequency Arra…
A Review of the Extended EUV Corona Observed by the Sun Watcher with Active Pixels and Image Processing (SWAP) Instrument
Berghmans, David; West, Matthew J.; Mierla, Marilena +7 more
The Sun Watcher with Active Pixels and Image Processing (SWAP) instrument onboard ESA's PRoject for On Board Autonomy 2 (PROBA2) has provided the first uncompressed, high-cadence, continuous, large field-of-view observations of the extended extreme-ultraviolet (EUV) corona for over a complete solar cycle. It has helped shape our understanding of t…
Observation of a Flare and Filament Eruption in Lyman-α on 8 September 2011 by the PRoject for OnBoard Autonomy/Large Yield Radiometer (PROBA2/LYRA)
Kretzschmar, M.; Dammasch, I. E.; Dominique, M. +3 more
The Large Yield Radiometer (LYRA) instrument onboard the PRoject for OnBoard Autonomy (PROBA2) observes the solar irradiance in four channels in the UV-EUV. One of these channels is centered around the hydrogen line at 121.6 nm. The solar Lyman-α emission line is an optically thick line mostly formed in the chromosphere. Although it is one of the …
Comparing the Sun Watcher Using Active Pixel System Detector and Image Processing Instrument to the Atmosphere Imaging Assembly Instrument Through Measurements of Polar Coronal Holes
West, Matthew J.; Pesnell, W. Dean; Kirk, Michael S. F. +2 more
The PRoject for OnBoard Autonomy 2/Sun Watcher using Active pixel system detector and image Processing (PROBA2/SWAP) instrument images the full-disk extreme ultraviolet (EUV) Sun using a complementary metal-oxide semiconductor active-pixel sensor (CMOS-APS) detector with a filter centered on a 174 Å passband at a cadence of one to two minutes. In …