Search Publications
The Solar Origin of an Intense Geomagnetic Storm on 1 December 2023: Successive Slipping and Eruption of Multiple Magnetic Flux Ropes
Hou, Yijun; Li, Ting; Feng, Li +12 more
The solar eruption that occurred on 28 November 2023 (SOL2023-11-28) triggered an intense geomagnetic storm on 1 December 2023. The associated terrestrial auroras manifested at the most southern latitudes in the northern hemisphere observed in the past two decades. In order to explore the profound geoeffectiveness of this event, we conducted a com…
Observations of the Polarized Solar Corona During the Annular Eclipse of 14 October 2023
West, Matthew J.; Alzate, Nathalia; Seaton, Daniel B. +10 more
We present results of a dual eclipse expedition to observe the solar corona from two sites during the annular solar eclipse of 14 October 2023 using a novel coronagraph designed to be accessible for amateurs and students to build and deploy. The coronagraph (CATEcor) builds on the standardized eclipse observing equipment developed for the Citizen …
Association Between a Failed Prominence Eruption and the Drainage of Mass from Another Prominence
Feng, Li; Lu, Lei; Li, Qiao +31 more
Sympathetic eruptions of solar prominences have been studied for decades, however, it is usually difficult to identify their causal links. Here, we present two failed prominence eruptions on 26 October 2022 and explore their connections. Using stereoscopic observations, the South prominence (PRO-S) erupts with untwisting motions, flare ribbons occ…
Calibration and Release of Magnetograms/Dopplergrams Obtained at the Mt. Wilson 150-Foot Tower Telescope (MWO)
Ulrich, Roger K.; Boyden, John; Tran, Tham
The Mt. Wilson Observatory archive of observations of solar disk magnetic fields, Doppler velocities, and spectral line intensities is a resource for studying the Sun's state from 1967 to 2013. Instrument changes/upgrades during this time must be considered when interpreting this record. Portions of this record have been previously released. This …
Asymmetric Hard X-ray Radiation of Two Ribbons in a Thermal-Dominated C-Class Flare
Lei, Shijun; Feng, Li; Lu, Lei +26 more
The asymmetry in hard X-ray (HXR) emission at the footpoints (FPs) of flare loops is a ubiquitous feature closely associated with nonthermal electron transport. In this study, we analyze the asymmetric HXR radiation at two flare ribbons, which is thermal-dominated during a long-duration C4.4 flare that occurred on March 20, 2023, combining multi-v…
Kink-and-Disconnection Failed Eruption in 3D
Chen, Wei; Gan, Weiqun; Mrozek, Tomasz +4 more
We present a case study of a failed eruption that accompanied an M1.5 GOES class solar flare. It was observed by STIX onboard Solar Orbiter, HXI onboard the Advanced Space-based Solar Observatory, AIA onboard Solar Dynamics Observatory, and WAVES onboard the STEREO-A. The important input is from stereoscopic hard X-ray (HXR) observations obtained …
Characterizing High-Energy Solar Proton Events with Energies Below and Above 100 MeV
Vainio, Rami; Valtonen, Eino; Al-Sawad, Amjad +1 more
We analyzed 58 high-energy proton events that occurred during the years 1996 – 2022. In 32 out of the 58 (55%) events, the proton energies extended up to
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
Online Catalog of Activity Events of Solar Cycle 24 Related to Active Regions
Tsvetkov, Tsvetan; Petrov, Nikola; Nakeva, Yoana
We present a statistical study on the relationship of solar dynamic events (solar flares and coronal mass ejections) with active regions during Solar Cycle 24 (December 2008–December 2019). Combining data from NOAA Space Weather Prediction Center and observations of Large Angle and Spectrometric Coronagraph (LASCO) onboard the Solar and Heliospher…
Long-Term Trends in Subsurface Flows of Solar Cycle 23 to 25
Komm, Rudolf
We study the long-term variation of the zonal and meridional flows from Solar Cycle 23 to 25 derived with ring-diagram analysis applied to Global Oscillation Network Group (GONG) and Helioseismic and Magnetic Imager (HMI) Dopplergrams. We focus mainly on the subsurface flows averaged over depths from 2.0 Mm to 11.6 Mm since their long-term variati…