Search Publications
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…
Improving the Spectral Resolution and Wavelength Scale of SDO/EVE MEGS-A Flare Observations
Chamberlin, Phillip; Gonzalez, Gabriela; Herde, Vicki
The Extreme ultraviolet Variability Experiment (EVE) is one of three instruments onboard the Solar Dynamics Observatory (SDO). This paper focuses on using the "A" channel on the Multiple EUV Grating Spectrographs (MEGS-A) on EVE, which measures wavelengths of 5 – 37 nm, to improve the wavelength scale accuracy and spectral resolution during solar …
Meridional Circulations of the Solar Magnetic Fields of Different Strength
Bilenko, Irina A.
The meridional circulation of the solar magnetic fields in Solar Cycles 21 – 24 was considered. Data from both ground-based and space observatories were used. Three types of time–latitude distributions of photospheric magnetic fields and their meridional circulations were identified depending on the magnetic-field intensity. (i) Low-strength magne…
Photospheric Stereoscopy: Direct Estimation of Solar Surface-Height Variations
Hirzberger, Johann; Solanki, Sami K.; Inhester, Bernd +1 more
The orbit of the Solar Orbiter mission carries it and the Polarimetric and Helioseismic Imager (PHI), which is onboard, away from the Sun–Earth line, opening up the first ever possibility of doing stereoscopy of solar photospheric structures. We present a method for a stereoscopic analysis of the height variations in the solar photosphere. This me…
IRIS Observational Approach to the Oscillatory and Damping Nature of Network and Internetwork Chromosphere Small-Scale Brightening (SSBs) and Their Unusual Dynamical and Morphological Differences in Different Regions on the Solar Disk
Tavabi, Ehsan; Sadeghi, Rayhaneh
One of the most exciting benefits of solar small-scale brightening is their oscillations. This study investigated the properties of small-scale brightening (SSBs) in different regions of the Sun and found that there are differences and similarities in the properties of oscillated and non-oscillated SSBs in different regions of the Sun, including q…