Search Publications
Immersed in Solar Physics
Hirayama, Tadashi
Since I have lived a rather ordinary life, my focus will center on what I have studied, with only exceptional personal matters being discussed. Nevertheless, rather new ideas are presented in Section 6.2 on the flare theory and in Section 9 on the mechanism of the 22-year solar cycle. These ideas have been included in light of my 90 years of age, …
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-…
Coronal Holes, Footpoint Reconnection, and the Origin of the Slow (and Fast) Solar Wind
Wang, Y. -M.
The tendency for low-speed solar wind to show greater spatiotemporal variability and different compositional properties from high-speed wind has led to the prevailing idea of a bimodal solar wind, in which fast wind comes from coronal holes and slow wind comes from coronal streamers. We present observational evidence that most of the slow wind ori…
Decomposing the AIA 304 Å Channel into Its Cool and Hot Components
Antolin, Patrick; Auchère, Frédéric; Soubrié, Elie +2 more
The AIA 304 Å channel on board the Solar Dynamics Observatory (SDO) offers a unique view of ≈105 K plasma emitting in the He II 304 Å line. However, when observing off-limb, the emission of the (small) cool structures in the solar atmosphere (such as spicules, coronal rain and prominence material) can be of the same order as the surrounding hot co…
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…
Multiwavelength Observations of Quasiperiodic Pulsations in the Impulsive Phase of an Eruptive Flare with the Hard X-Ray Imager On Board ASO-S and Other Instruments
Chen, Wei; Warmuth, Alexander; Su, Yang +7 more
We investigated the quasiperiodic pulsations (QPPs) of the X1.2 solar flare (SOL2023-01-06T00:57) based on multi-instrument observations, especially the Hard X-ray Imager (HXI) on board the Advanced Space-based Solar Observatory (ASO-S). The quasiperiod of ≈27 s was identified in hard X-rays (HXR) and microwaves using the Markov Chain Monte Carlo …
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…