Search Publications
Photometric Comparison of Metis and LASCO-C2 Polarized Brightness Images
Susino, Roberto; Romoli, Marco; Burtovoi, Aleksandr +15 more
The Metis coronagraph onboard Solar Orbiter and the LASCO-C2 coronagraph onboard SoHO both acquire white light polarized brightness (pB) images of the solar corona. When the Sun–Solar Orbiter distance is less than 0.85 AU, i.e., outside orbital segments around aphelia, the range of elongations covered by the fields-of-view of the two instruments o…
Mysteries of the 17 May 2012 Solar Event Responsible for GLE71: II. Features of the Flare and Its Atypical Microwave Emission
Grechnev, V. V.; Lysenko, A. L.; Kiselev, V. I. +2 more
As known, large near-Earth proton enhancements usually occur after major eruptive solar flares accompanied by strong microwave bursts. Typically, the spectral-maximum frequency of such a burst exceeds 10 GHz, and the flux exceeds
On the Hierarchical Relationship Between Type-II Radio Bursts and the Associated Coronal Mass Ejections
Gopalswamy, N.; Yashiro, S.; Mäkelä, P. +3 more
Using Type-II radio bursts from Wind/WAVES and the associated coronal mass ejections (CMEs) from SOHO/LASCO, Gopalswamy et al. (2005) found a hierarchical relationship between the wavelength range of the Type-II bursts and the CME kinetic energy. Under 'DH (Decametric–Hectometric) Type-II bursts', they have included m (metric)-DH, pure DH, and DH-…
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…