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
Probing Velocity Dispersion Inside Coronal Mass Ejections: New Insights on Their Initiation
Mierla, Marilena; Reiss, Martin A.; Banerjee, Dipankar +4 more
This work studies the kinematics of the leading edge and the core of six coronal mass ejections (CMEs) in the combined field of view of Sun Watcher using Active Pixel System detector and Image Processing (SWAP) on board PRoject for On-Board Autonomy (PROBA-2) and the ground-based K-Cor coronagraph of the Mauna Loa Solar Observatory. We report, for…
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…
The Thermosphere Is a Drag: The 2022 Starlink Incident and the Threat of Geomagnetic Storms to Low Earth Orbit Space Operations
Berger, T. E.; Dominique, M.; Thiemann, E. +6 more
On 03 February 2022, SpaceX launched 49 Starlink satellites, 38 of which re-entered the atmosphere on or about 07 February 2022 due to unexpectedly high atmospheric drag. We use empirical model (NRLMSIS, JB08, and HASDM) outputs as well as solar extreme ultraviolet occultation and high-fidelity accelerometer data to show that thermospheric density…
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 …
Global Energetics of Solar Powerful Events on 2017 September 6
Lu, Lei; Dresing, Nina; Wang, Jincheng +9 more
Solar flares and coronal mass ejections (CMEs) are thought to be the most powerful events on the Sun. They can release energy as high as ~1032 erg in tens of minutes, and also can release solar energetic particles (SEPs) into interplanetary space. We explore global energy budgets of solar major eruptions that occurred on 2017 September …
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 …
Lower-ionosphere electron density and effective recombination coefficients from multi-instrument space observations and ground VLF measurements during solar flares
Dominique, Marie; Žigman, Vida; Grubor, Davorka +2 more
A new model to predict the electron density and effective recombination coefficient of the lower ionosphere under solar flare conditions is presented. This model relies on space-borne solar irradiance measurements in coincidence with ground recorded active transmissions of Very Low Frequency (VLF), (<30 kHz) signals. Use is made of the irradian…