Search Publications
High-Resolution Observation of Blowout Jets Regulated by Sunspot Rotation
Veronig, Astrid M.; Gan, Weiqun; Liu, Rui +4 more
Coronal jets are believed to be the miniature version of large-scale solar eruptions. In particular, the eruption of a minifilament inside the base arch is suggested to be the trigger and even driver of blowout jets. Here, we propose an alternative triggering mechanism, based on high-resolution Hα observations of a blowout jet associated with a mi…
Modeling Global Magnetic-Flux Emergence in Bipolar Solar-Active Regions
Démoulin, Pascal; Mandrini, Cristina H.; López Fuentes, Marcelo +2 more
Active regions (ARs) appear in the solar atmosphere as a consequence of the emergence of magnetic-flux ropes (FR). In this study, we use Bayesian methods to analyze line-of-sight magnetograms of emerging ARs. We employ a FR model consisting of a half-torus field structure based on eight parameters. The goal is to derive constrained physical parame…
Analysis of Overtones in Transverse Oscillations of Coronal Loops of an Active Region
K., Safna Banu; Maurya, Ram Ajor
We investigate the fundamental mode and overtones in the transverse oscillations of coronal loops associated with an active region using intensity observations taken by the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO). The fundamental periods of the two selected coronal loops are found to be 17.0 minutes and 15.2…
Early Evolution of Earth-Directed Coronal Mass Ejections in the Vicinity of Coronal Holes
Dumbović, Mateja; Temmer, Manuela; Vršnak, Bojan +3 more
We investigate the deflection and rotation behaviour of 49 Earth-directed coronal mass ejections (CMEs) spanning the period from 2010 to 2020 aiming to understand the potential influence of coronal holes (CHs) on their trajectories. Our analysis incorporates data from coronagraphic observations captured from multiple vantage points, as well as ext…
Helioseismic Constraints: Past, Current, and Future Observations
Appourchaux, Thierry
I will review the history of the helioseismic observations since the beginning of the field. I will explain how each instrument was designed based upon the required observables, and to which modes these instruments are sensitive. The impact of these sensitivities on the rotation and structure inversion will be developed. I will conclude with what …
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 STIX Imaging Concept
Volpara, Anna; Massa, Paolo; Krucker, Säm +18 more
We provide a mathematical description of the imaging concept of the Spectrometer/Telescope for Imaging X-rays (STIX) onboard Solar Orbiter. Specifically, we describe the STIX indirect-imaging technique, which is based on spatial modulation of the X-ray photon flux by means of tungsten grids, and we show that each of 30 STIX imaging sub-collimators…
Statistical Analysis of Interplanetary Shocks from Mercury to Jupiter
Janvier, Miho; Nieves-Chinchilla, Teresa; Démoulin, Pascal +3 more
In situ observations of interplanetary (IP) coronal mass ejections (ICMEs) and IP shocks are important to study as they are the main components of solar activity. Hundreds of IP shocks have been detected by various space missions at different times and heliocentric distances. Some of these are followed by clearly identified drivers, while some oth…
The Possible Cause of Most Intense Geomagnetic Superstorm of the 21st Century on 20 November 2003
Bhaskar, Ankush; Vemareddy, P.; Raghav, Anil +6 more
An extreme geomagnetic storm has the potential to affect various technologies and activities in space and on the ground, e.g., power grids, oil and gas industries, communications, ground transportation, satellite infrastructure, global navigation satellite systems, aviation, etc. Therefore, it is considered a major source of risk by various govern…