Search Publications
Deconstructing the Properties of Solar Super Active Region 13664 in the Context of the Historic Geomagnetic Storm of 2024 May 10–11
Nandy, Dibyendu; Jaswal, Priyansh; Sinha, Suvadip
Active regions (ARs) are sites of strong magnetic fields on the solar surface whose size can be several times that of Earth. They spawn dynamic activity, sometimes resulting in severe space weather. Some ARs characterized by extraordinary magnetic properties and exhibiting extreme activity are termed as super active regions (SARs). Recently, solar…
Shock and SEP Modeling Study for the 2022 September 5 SEP Event
Lario, D.; Jebaraj, I. C.; Mitchell, D. G. +10 more
On 2022 September 5, during Parker Solar Probe's (PSP) 13th encounter, a fast shock wave and a related solar energetic particle (SEP) event were observed as the spacecraft approached the perihelion of its orbit. Observations from the Integrated Science Investigation of the Sun (IS⊙IS) instrument suite show that SEPs arrived at the spacecraft with …
Differentiating the Acceleration Mechanisms in the Slow and Alfvénic Slow Solar Wind
D'Amicis, Raffaella; Reeves, Katharine K.; Stawarz, Julia E. +18 more
In the corona, plasma is accelerated to hundreds of kilometers per second and heated to temperatures hundreds of times hotter than the Sun's surface before it escapes to form the solar wind. Decades of space-based experiments have shown that the energization process does not stop after it escapes. Instead, the solar wind continues to accelerate, a…
Transonic Turbulence and Density Fluctuations in the Near-Sun Solar Wind
Li, H.; Zank, G. P.; Zhao, L. -L. +2 more
We use in situ measurements from the first 19 encounters of Parker Solar Probe and the most recent five encounters of Solar Orbiter to study the evolution of the turbulent sonic Mach number Mt (the ratio of the amplitude of velocity fluctuations to the sound speed) with radial distance and its relationship to density fluctuations. We fo…
Near- and Mid-ultraviolet Observations of X-6.3 Flare on 2024 February 22 Recorded by the Solar Ultraviolet Imaging Telescope on board Aditya-L1
Solanki, Sami K.; Tripathi, Durgesh; Nandy, Dibyendu +10 more
Solar flares are regularly observed in extreme-ultraviolet soft X-rays (SXRs) and hard X-rays (HXRs). However, those in near- and mid-ultraviolet are sparse. The Solar Ultraviolet Imaging Telescope (SUIT) on board the Aditya-L1, launched on 2023 September 2, provides regular observations in the 200–400 nm wavelength range through 11 filters. Here,…
Quasi-parallel Antisunward-propagating Whistler Waves Associated with the Electron Deficit in the Near-Sun Solar Wind: Particle-in-cell Simulation
Verscharen, Daniel; Coburn, Jesse T.; Innocenti, Maria Elena +1 more
In situ observations of the solar wind have shown that the electron velocity distribution function (VDF) consists of a quasi-Maxwellian core, comprising most of the electron population, and two sparser components: the halo, which are suprathermal and quasi-isotropic electrons, and an escaping beam population, the strahl. Recent Parker Solar Probe …
Testing the Flux Rope Paradigm for Coronal Mass Ejections Using a Three-spacecraft Encounter Event
Hess, Phillip; Wood, Brian E.
We present a 3D morphological and field reconstruction of a coronal mass ejection (CME) from 2023 November 28, which hits three spacecraft near 1 au: Wind at Earth's L1 Lagrange point, STEREO-A with a longitudinal separation of 6
Statistics of the Interplanetary Magnetic Field from 0.1 to 30 au. I. Distribution Character
Zong, Qiugang; He, Jiansen; Yang, Liu +7 more
This study investigates the directional and intensity distributions of the interplanetary magnetic field (IMF) across a heliocentric distance range of approximately 0.1–30 au. Measurements from multiple spacecraft reveal that these distributions align closely with the Parker spiral configuration in general. Nevertheless, the deviation from the mod…
Longitudinal Dependence of Heavy Ion Composition in the 2021 October 28 Ground Level Enhancement Event
Mitchell, D. G.; McComas, D. J.; Mitchell, J. G. +19 more
The 2021 October 28 solar energetic particle (SEP) event was a rare ground level enhancement (GLE) event, where secondary particles from the interactions of SEPs with the Earth's atmosphere were detected by neutron monitors on the ground. A number of papers have examined the solar signatures, neutron monitor observations, and the characteristics o…
On the Existence of Long-period Decayless Oscillations in Short Active Region Loops
Van Doorsselaere, Tom; Lim, Daye; Berghmans, David +5 more
Decayless kink oscillations, characterized by their lack of decay in amplitude, have been detected in coronal loops of varying scales in active regions, the quiet Sun, and coronal holes. Short-period (<50 s) decayless oscillations have been detected in short loops (< 50 Mm) within active regions. Nevertheless, long-period decayless oscillati…