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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…
A Revised Graduated Cylindrical Shell Model and its Application to a Prominence Eruption
Zhang, Qing-Min; Hou, Zhen-Yong; Bai, Xian-Yong
In this paper, the well-known graduated cylindrical shell (GCS) model is slightly revised by introducing longitudinal and latitudinal deflections of prominences originating from active regions (ARs). Subsequently, it is applied to the three-dimensional (3D) reconstruction of an eruptive prominence in AR 13110, which produced an M1.7 class flare an…
High-Cadence Observations of Magnetic Field Dynamics and Photospheric Emission Sources in the Eruptive Near-the-Limb X4.9 Solar Flare on 25 February, 2014: Evidences for Two-Stage Magnetic Reconnection during the Impulsive Phase
Zimovets, I. V.; Sharykin, I. N.; Radivon, A. V.
We present an analysis of the pre-limb eruptive X4.9 solar flare on February 25, 2014, by means of which we confirm a hypothesis of the two-stage energy release corresponding to two magnetic reconnection regimes in the flare impulsive phase. This flare is selected, firstly, because of its morphological peculiarities suggesting the presence of the …