Search Publications
Super-Resolution of SOHO/MDI Magnetograms of Solar Active Regions Using SDO/HMI Data and an Attention-Aided Convolutional Neural Network
Xu, Yan; Wang, Haimin; Wang, Jason T. L. +4 more
Image super-resolution is an important subject in image processing and recognition. Here, we present an attention-aided convolutional neural network for solar image super-resolution. Our method, named SolarCNN, aims to enhance the quality of line-of-sight (LOS) magnetograms of solar active regions (ARs) collected by the Michelson Doppler Imager (M…
Observation of a Large-Scale Filament Eruption Initiated by Two Small-Scale Erupting Filaments Pushing Out from Below
Song, Yongliang; Zhang, Mei; Ji, Kaifan +9 more
Filament eruptions often result in flares and coronal mass ejections (CMEs). Most studies attribute the filament eruptions to their instabilities or magnetic reconnection. In this study, we report a unique observation of a filament eruption whose initiation process has not been reported before. This large-scale filament, with a length of about 360…
CME-Flare Association and the Role of Reconnection in CME Acceleration
Reva, Anton; Kirichenko, Alexey; Bogachev, Sergey +1 more
The association of coronal mass ejections (CMEs) with flares is related to the question of whether reconnection is necessary for the CME eruption. Indeed, if reconnection happens during a CME eruption, the plasma is heated, which can be observed as a flare. In this work, we study the CME-flare association using data obtained with the Mg XII spectr…
The "SEP Clock": A Discussion of First Proton Arrival Times in Wide-Spread Solar Energetic Particle Events
Posner, A.; Richardson, I. G.; Strauss, R. D. -T.
This work analyzes the appearance of wide-spread deka-MeV solar energetic proton (SEP) events, in particular the arrival of the first protons within ≈ 4.5 – 45 MeV measured at Earth–Sun L1, and their relationship with their relative solar source longitude. The definition of "wide-spread SEP event" for this study refers to events that are observed …
Mysteries of the 17 May 2012 Solar Event Responsible for GLE71. I. CME Development and the Role of Disturbances Excited by Eruptions
Firoz, K. A.; Grechnev, V. V.; Lysenko, A. L. +3 more
The SOL2012-05-17 event is remarkable in that it caused one of two ground-level enhancements (GLE71) in Solar Cycle 24. Despite the efforts spent studying this solar event, some aspects of it remain unclear. This relates to the development of a coronal mass ejection (CME), the history of the shock wave, and the flare. Our measurements reveal the f…
Spectra and Anisotropy of Solar Energetic Protons During GLE #65 on 28 October, 2003 and GLE #66 on 29 October, 2003
Mishev, Alexander L.; Koldobskiy, Sergey A.; Larsen, Nicholas +1 more
Solar Cycle 23 was the most active in ground-level enhancements (GLEs) with 16 events registered by the global neutron monitor network. In this paper, we study a very active period in October–November, 2003, which revealed an intense solar activity burst that led to several eruptive processes and produced a sequence of three GLEs. By applying stat…
The Sun's Large-Scale Flows I: Measurements of Differential Rotation & Torsional Oscillation
Basu, Sarbani; Pevtsov, Alexei A.; DeRosa, Marc L. +13 more
We have developed a comprehensive catalog of the variable differential rotation measured near the solar photosphere. This catalog includes measurements of these flows obtained using several techniques: direct Doppler, granule tracking, magnetic pattern tracking, global helioseismology, as well as both time-distance and ring-diagram methods of loca…
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 …
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 …