Search Publications
High-Resolution Spectral and Anisotropy Characteristics of Solar Protons During the GLE N∘73 on 28 October 2021 Derived with Neutron-Monitor Data Analysis
Vainio, Rami; Riihonen, Esa; Mishev, Alexander L. +4 more
The first ground-level enhancement of the current Solar Cycle 25 occurred on 28 October 2021. It was observed by several space-borne and ground-based instruments, specifically neutron monitors. A moderate count-rate increase over the background was observed by high-altitude polar stations on the South Pole and Dome C stations at the Antarctic plat…
Transverse Coronal-Loop Oscillations Induced by the Non-radial Eruption of a Magnetic Flux Rope
Li, D.; Zhang, Q. M.; Lu, L. +2 more
We investigate the transverse coronal-loop oscillations induced by the eruption of a prominence-carrying flux rope on 7 December 2012. The flux rope, originating from NOAA Active Region (AR) 11621, was observed in extreme-ultraviolet (EUV) wavelengths by the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) spacecraft…
Group Sunspot Numbers: A New Reconstruction of Sunspot Activity Variations from Historical Sunspot Records Using Algorithms from Machine Learning
Velasco Herrera, Víctor Manuel; Soon, Willie; Hoyt, Douglas V. +1 more
Historical sunspot records and the construction of a comprehensive database are among the most sought after research activities in solar physics. Here, we revisit the issues and remaining questions on the reconstruction of the so-called group sunspot numbers (GSN) that was pioneered by D. Hoyt and colleagues. We use the modern tools of artificial …
Invited Review: Short-term Variability with the Observations from the Helioseismic and Magnetic Imager (HMI) Onboard the Solar Dynamics Observatory (SDO): Insights into Flare Magnetism
Kazachenko, Maria D.; Welsch, Brian T.; Albelo-Corchado, Marcel F. +1 more
Continuous vector magnetic-field measurements by the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO) allow us to study magnetic-field properties of many flares. Here, we review new observational aspects of flare magnetism described using SDO data, including statistical properties of magnetic-reconnection fluxes …
Extreme-Ultraviolet Wave and Accompanying Loop Oscillations
Awasthi, Arun Kumar; Schmieder, Brigitte; Joshi, Reetika +2 more
We present the observations of an extreme-ultraviolet (EUV) wave, which originated from the active region (AR) NOAA 12887 on 28 October 2021, and its impact on neighboring loops. The event was observed by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO) satellite at various wavebands and by the Solar TErrestrial…
A Simple Radial Gradient Filter for Batch-Processing of Coronagraph Images
Pant, Vaibhav; Banerjee, Dipankar; Patel, Ritesh +1 more
Images of the extended solar corona, as observed by different white-light coronagraphs, include the K- and F-corona and suffer from a radial variation in intensity. These images require separation of the two coronal components with some additional image-processing to reduce the intensity gradient and analyse the structures and processes occurring …
Interplanetary Sheaths and Corotating Interaction Regions: A Comparative Statistical Study on Their Characteristics and Geoeffectiveness
Hajra, Rajkumar; Sunny, Jibin V.; Babu, Megha +1 more
Interplanetary sheaths and corotating interaction regions (CIRs), while having different solar sources, represent turbulent solar-wind plasma and magnetic field that can perturb the Earth's magnetosphere. We explore long-term solar-wind measurements upstream of the Earth during Solar Cycle 24, from January 2008 to December 2019, to compare their s…
Observation of the Solar Corona Using Radio Scintillation with the Akatsuki Spacecraft: Difference Between Fast and Slow Wind
Matsumoto, Takuma; Pätzold, Martin; Imamura, Takeshi +8 more
The properties of the coronal plasma at heliocentric distances of 1.5 - 8.9 R⊙ (solar radii) were studied with radio-occultation observations using JAXA's Akatsuki spacecraft in 2016. Physical parameters that characterize the solar wind were retrieved from the intensity-scintillation time series by fitting a theoretical spectrum to the …
Extracting the Heliographic Coordinates of Coronal Rays Using Images from WISPR/Parker Solar Probe
Riley, P.; Qiu, J.; Stenborg, G. +5 more
The Wide-field Imager for Solar Probe (WISPR) onboard Parker Solar Probe (PSP), observing in white light, has a fixed angular field of view, extending from 13.5∘ to 108∘ from the Sun and approximately 50∘ in the transverse direction. In January 2021, on its seventh orbit, PSP crossed the heliospheric current sheet …
Multiwavelength Observations of a Partial Filament Eruption on 13 June 2011
Li, Dong; Zhang, Qingmin; Zhang, Yanjie +2 more
In this paper, we report the multiwavelength observations of the partial filament eruption associated with a C1.2 class flare in NOAA active region 11236 on 13 June 2011. The event occurred at the eastern limb in the field of view (FOV) of Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) spacecraft and was close to t…