Search Publications
Defining the Middle Corona
Giordano, Silvio; Andretta, Vincenzo; Reeves, Katharine K. +39 more
The middle corona, the region roughly spanning heliocentric distances from 1.5 to 6 solar radii, encompasses almost all of the influential physical transitions and processes that govern the behavior of coronal outflow into the heliosphere. The solar wind, eruptions, and flows pass through the region, and they are shaped by it. Importantly, the reg…
The STIX Imaging Concept
Volpara, Anna; Massa, Paolo; Krucker, Säm +18 more
We provide a mathematical description of the imaging concept of the Spectrometer/Telescope for Imaging X-rays (STIX) onboard Solar Orbiter. Specifically, we describe the STIX indirect-imaging technique, which is based on spatial modulation of the X-ray photon flux by means of tungsten grids, and we show that each of 30 STIX imaging sub-collimators…
Statistical Analysis of Interplanetary Shocks from Mercury to Jupiter
Janvier, Miho; Nieves-Chinchilla, Teresa; Démoulin, Pascal +3 more
In situ observations of interplanetary (IP) coronal mass ejections (ICMEs) and IP shocks are important to study as they are the main components of solar activity. Hundreds of IP shocks have been detected by various space missions at different times and heliocentric distances. Some of these are followed by clearly identified drivers, while some oth…
The Possible Cause of Most Intense Geomagnetic Superstorm of the 21st Century on 20 November 2003
Bhaskar, Ankush; Vemareddy, P.; Raghav, Anil +6 more
An extreme geomagnetic storm has the potential to affect various technologies and activities in space and on the ground, e.g., power grids, oil and gas industries, communications, ground transportation, satellite infrastructure, global navigation satellite systems, aviation, etc. Therefore, it is considered a major source of risk by various govern…
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<…