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Parker Solar Probe: Four Years of Discoveries at Solar Cycle Minimum
McComas, D. J.; Bale, S. D.; Matteini, L. +55 more
Launched on 12 Aug. 2018, NASA's Parker Solar Probe had completed 13 of its scheduled 24 orbits around the Sun by Nov. 2022. The mission's primary science goal is to determine the structure and dynamics of the Sun's coronal magnetic field, understand how the solar corona and wind are heated and accelerated, and determine what processes accelerate …
Waves in the lower solar atmosphere: the dawn of next-generation solar telescopes
Stangalini, Marco; Jess, David B.; Jafarzadeh, Shahin +3 more
Waves and oscillations have been observed in the Sun's atmosphere for over half a century. While such phenomena have readily been observed across the entire electromagnetic spectrum, spanning radio to gamma-ray sources, the underlying role of waves in the supply of energy to the outermost extremities of the Sun's corona has yet to be uncovered. Of…
The 17 April 2021 widespread solar energetic particle event
Holmström, M.; Grande, M.; Palmerio, E. +46 more
Context. A complex and long-lasting solar eruption on 17 April 2021 produced a widespread solar energetic particle (SEP) event that was observed by five longitudinally well-separated observers in the inner heliosphere that covered distances to the Sun from 0.42 to 1 au: BepiColombo, Parker Solar Probe, Solar Orbiter, STEREO A, and near-Earth space…
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…
Machine learning in solar physics
Cheung, Mark C. M.; Asensio Ramos, Andrés; Chifu, Iulia +1 more
The application of machine learning in solar physics has the potential to greatly enhance our understanding of the complex processes that take place in the atmosphere of the Sun. By using techniques such as deep learning, we are now in the position to analyze large amounts of data from solar observations and identify patterns and trends that may n…
Direct observations of a complex coronal web driving highly structured slow solar wind
Chitta, L. P.; Seaton, D. B.; DeForest, C. E. +2 more
The solar wind consists of continuous streams of charged particles that escape into the heliosphere from the Sun, and is split into fast and slow components, with the fast wind emerging from the interiors of coronal holes. Near the ecliptic plane, the fast wind from low-latitude coronal holes is interspersed with a highly structured slow solar win…
Multiple injections of energetic electrons associated with the flare and CME event on 9 October 2021
Vainio, R.; Wiegelmann, T.; Krupar, V. +12 more
Context. We study the solar energetic particle (SEP) event observed on 9 October 2021 by multiple spacecraft, including Solar Orbiter. The event was associated with an M1.6 flare, a coronal mass ejection, and a shock wave. During the event, high-energy protons and electrons were recorded by multiple instruments located within a narrow longitudinal…
Type II radio bursts and their association with coronal mass ejections in solar cycles 23 and 24
Kilpua, E. K. J.; Kumari, A.; Morosan, D. E. +1 more
Context. Meter-wavelength type II solar radio bursts are thought to be the signatures of shock-accelerated electrons in the corona. Studying these bursts can give information about the initial kinematics, dynamics, and energetics of coronal mass ejections (CMEs) in the absence of white-light observations.
Aims: We investigate the occurrence o…
Long-term changes in solar activity and irradiance
Chatzistergos, Theodosios; Krivova, Natalie A.; Yeo, Kok Leng
The Sun is the main energy source to Earth, and understanding its variability is of direct relevance to climate studies. Measurements of total solar irradiance (TSI) exist since 1978, but this is too short compared to climate-relevant time scales. Coming from a number of different instruments, these measurements require a cross-calibration, which …
Rotation and interaction of the CMEs of September 8 and 10, 2014, tested with EUHFORIA
Poedts, Stefaan; Scolini, Camilla; Schmieder, Brigitte +1 more
Context. Solar coronal mass ejections (CMEs) can catch up and interact with preceding CMEs and solar wind structures to undergo rotation and deflection during their propagation. Aim. We aim to show how the interactions of a CME in the corona and heliosphere can play a significant role in altering its geoeffectiveness as predicted at the time of it…