Search Publications
Rapid Rotation of an Erupting Prominence and the Associated Coronal Mass Ejection on 13 May 2013
Zhang, Qingmin; Ji, Haisheng; Zhou, Yuhao
In this paper, we report the multiwavelength observations of an erupting prominence and the associated coronal mass ejection (CME) on 13 May 2013. The event occurs behind the western limb in the field of view of the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO) spacecraft. The prominence is supported by a highly …
The First Survey of Quiet Sun Features Observed in Hard X-Rays with NuSTAR
Krucker, Säm; White, Stephen M.; Grefenstette, Brian W. +5 more
We present the first survey of quiet Sun features observed in hard X-rays (HXRs), using the Nuclear Spectroscopic Telescope ARray (NuSTAR), a HXR focusing optics telescope. The recent solar minimum, combined with NuSTAR's high sensitivity, has presented a unique opportunity to perform the first HXR imaging spectroscopy on a range of features in th…
Generating Photospheric Vector Magnetograms of Solar Active Regions for SOHO/MDI Using SDO/HMI and BBSO Data with Deep Learning
Xu, Yan; Jing, Ju; Wang, Haimin +6 more
Solar activity is often caused by the evolution of solar magnetic fields. Magnetic field parameters derived from photospheric vector magnetograms of solar active regions (ARs) have been used to analyze and forecast eruptive events, such as solar flares and coronal mass ejections. Unfortunately, the most recent Solar Cycle 24 was relatively weak wi…
Forecasting Heliospheric CME Solar-Wind Parameters Using the UCSD Time-Dependent Tomography and ISEE Interplanetary Scintillation Data: The 10 March 2022 CME
Saito, Yoshifumi; Yokota, Shoichiro; Barthe, Alain +15 more
Remotely sensed interplanetary scintillation (IPS) data from the Institute for Space-Earth Environmental Research (ISEE), Japan, allows a determination of solar-wind parameters throughout the inner heliosphere. We show the 3D analysis technique developed for these data sets that forecast plasma velocity, density, and component magnetic fields at E…
Solar Electron Beam Velocities That Grow Langmuir Waves in the Inner Heliosphere
Reid, Hamish A. S.; Lorfing, Camille Y.
Solar accelerated electron beams, a component of space weather, are emitted by eruptive events at the Sun. They interact with the ambient plasma to grow Langmuir waves, which subsequently produce radio emission, changing the electrons' motion through space. Solar electron beam-plasma interactions are simulated using a quasilinear approach to kinet…
Comparison Between Radio Loud and Radio Quiet Fast CMEs: A Reason for Radio Quietness
Shanmugaraju, A.; Ebenezer, E.; Syed Ibrahim, M.
It is well known that fast CMEs are mostly associated with magnetohydrodynamic (MHD) shocks in the solar corona, forming type-II radio bursts. However, the absence of type-II radio bursts is not uncommon. Herein, we aim to analyze the differences between the radio loud (RL) and radio quiet (RQ) fast Coronal Mass Ejections (CMEs) (speed ≥ 900 km s<…
The SWAP Filter: A Simple Azimuthally Varying Radial Filter for Wide-Field EUV Solar Images
Berghmans, David; Rachmeler, Laurel A.; West, Matthew J. +5 more
We present the SWAP Filter: an azimuthally varying, radial normalizing filter specifically developed for EUV images of the solar corona, named for the Sun Watcher with Active Pixels and Image Processing (SWAP) instrument on the Project for On-Board Autonomy 2 (PROBA2) spacecraft. We discuss the origins of our technique, its implementation and key …
Cyclical Behaviors of Sunspot-Group Tilt Angles in Solar Cycles 21 - 23
Gao, Peng-Xin
Based on the Debrecen Photoheliographic Data (DPD) sunspot catalog, we investigate the cyclical behaviors of tilt angles of all sunspot groups (SGs) and SGs with angular separation constraint S >2.5∘ in Solar Cycles (SCs) 21 - 23. It is found that, the cyclical behaviors of tilt angles during SC 23 are different from those of SCs 21 …
Explosive Events in the Quiet Sun Near and Beyond the Solar Limb Observed with the Interface Region Imaging Spectrograph (IRIS)
Vial, J. -C.; Alissandrakis, C. E.
We study point-like explosive events (EE), characterized by emission in the far wings of spectral lines, in a quiet region near the South Pole, using Interface Region Imaging Spectrograph (IRIS) spectra at two slit positions, slit-jaw (SJ) observations, and Atmospheric Imaging Assembly (AIA) images. The events were best visible in Si IV spectra; t…
On the Periodicities in Solar Rotation and Activity Determined from Sunspot-Group Data and Possible Connection with Rossby-Like Waves
Hanslmeier, Arnold; Ruždjak, Domagoj; Brajša, Roman +2 more
Analyses of solar rotation and activity, and their variations, can improve the understanding of the formation and interaction of the solar-activity bands and therefore give important observational constraints on the modelling of the solar dynamo and improve the forecast capability in solar activity and space weather. Sunspot-position data obtained…