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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 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…
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 …
Generating Photospheric Vector Magnetograms of Solar Active Regions for SOHO/MDI Using SDO/HMI and BBSO Data with Deep Learning
Xu, Yan; Jing, Ju; Wang, Haimin +6 more
Solar activity is often caused by the evolution of solar magnetic fields. Magnetic field parameters derived from photospheric vector magnetograms of solar active regions (ARs) have been used to analyze and forecast eruptive events, such as solar flares and coronal mass ejections. Unfortunately, the most recent Solar Cycle 24 was relatively weak wi…
Forecasting Heliospheric CME Solar-Wind Parameters Using the UCSD Time-Dependent Tomography and ISEE Interplanetary Scintillation Data: The 10 March 2022 CME
Saito, Yoshifumi; Yokota, Shoichiro; Barthe, Alain +15 more
Remotely sensed interplanetary scintillation (IPS) data from the Institute for Space-Earth Environmental Research (ISEE), Japan, allows a determination of solar-wind parameters throughout the inner heliosphere. We show the 3D analysis technique developed for these data sets that forecast plasma velocity, density, and component magnetic fields at E…
Comparison Between Radio Loud and Radio Quiet Fast CMEs: A Reason for Radio Quietness
Shanmugaraju, A.; Ebenezer, E.; Syed Ibrahim, M.
It is well known that fast CMEs are mostly associated with magnetohydrodynamic (MHD) shocks in the solar corona, forming type-II radio bursts. However, the absence of type-II radio bursts is not uncommon. Herein, we aim to analyze the differences between the radio loud (RL) and radio quiet (RQ) fast Coronal Mass Ejections (CMEs) (speed ≥ 900 km s<…
Cyclical Behaviors of Sunspot-Group Tilt Angles in Solar Cycles 21 - 23
Gao, Peng-Xin
Based on the Debrecen Photoheliographic Data (DPD) sunspot catalog, we investigate the cyclical behaviors of tilt angles of all sunspot groups (SGs) and SGs with angular separation constraint S >2.5∘ in Solar Cycles (SCs) 21 - 23. It is found that, the cyclical behaviors of tilt angles during SC 23 are different from those of SCs 21 …
On the Periodicities in Solar Rotation and Activity Determined from Sunspot-Group Data and Possible Connection with Rossby-Like Waves
Hanslmeier, Arnold; Ruždjak, Domagoj; Brajša, Roman +2 more
Analyses of solar rotation and activity, and their variations, can improve the understanding of the formation and interaction of the solar-activity bands and therefore give important observational constraints on the modelling of the solar dynamo and improve the forecast capability in solar activity and space weather. Sunspot-position data obtained…
Behaviour of 27-Day and 13.5-Day Periodicities in Galactic Cosmic Particles as Observed by Spacecraft and Neutron Monitors During Different Solar Polarity Cycles
Kotzé, Pieter
An analysis has been made of the behaviour of the 27-day and 13.5-day periodicities in proton, C, and O galactic-cosmic-ray (GCR) particles at different energies as observed by the Advanced Composition Explorer (ACE) and SOHO (Solar and Heliospheric Observatory) spacecraft during both Solar Cycles 23 and 24. In addition, the behaviour of the 27-da…
Eruptive Flare, CME, and Shock Wave in the 25 August 2001 High-Energy Solar Event
Grechnev, V. V.; Kochanov, A. A.; Uralov, A. M.
The major SOL2001-08-25 event produced a fast coronal mass ejection (CME: 1430 km s−1), strong flare emissions in hard X-rays and γ -rays extending to high energies, and neutrons detected both on spacecraft and by a low-latitude neutron monitor. To supplement the probable picture of this outstanding event, we reconstruct kinematic plots…