Results 51 to 60 of about 14,496 (257)

Reconstruction of Two‐Dimensional Magnetohydrodynamic and Hall Magnetohydrodynamic Equilibria in Space Using Physics‐Informed Neural Networks

open access: yesJournal of Geophysical Research: Machine Learning and Computation, Volume 3, Issue 2, April 2026.
Abstract We present a novel data analysis technique based on physics‐informed neural networks (PINNs) to reconstruct two‐dimensional (2D) magnetohydrodynamic (MHD) and Hall MHD equilibria in a space plasma from in situ spacecraft measurements. Our method incorporates the steady‐state MHD or Hall MHD equations—a set of partial differential equations ...
Hiroshi Hasegawa   +3 more
wiley   +1 more source

Detection of a Magnetic Discontinuity in the Upper Solar Chromosphere Associated with a Coronal Loop Brightening Observed by CLASP2.1

open access: yesThe Astrophysical Journal
We report the first detection of a magnetic discontinuity in the upper solar chromosphere associated with a coronal loop brightening. Our findings are based on novel observations obtained by the Chromospheric LAyer SpectroPolarimeter (CLASP2.1 ...
Donguk Song   +17 more
doaj   +1 more source

Two-dimensional Radiative Magnetohydrodynamic Simulations of Partial Ionization in the Chromosphere. II. Dynamics and Energetics of the Low Solar Atmosphere

open access: yes, 2017
We investigate the effects of interactions between ions and neutrals on the chromosphere and overlying corona using 2.5D radiative MHD simulations with the Bifrost code.
Carlsson, Mats   +5 more
core   +1 more source

Reconstructing Historical Solar Indices for Predicting Past Space Weather Events

open access: yesSpace Weather, Volume 24, Issue 4, April 2026.
Abstract Modeling and forecasting the near‐Earth space environment, specifically the thermosphere, is particularly important because it affects the motion of low‐Earth orbit objects through atmospheric drag. Solar indices such as F10.7, S10.7, M10.7, and Y10.7 are commonly used as inputs to ionospheric and thermospheric density models.
Poshan Belbase   +4 more
wiley   +1 more source

Does a nonmagnetic solar chromosphere exist?

open access: yesThe Astrophysical Journal, 1995
4 pages, uuencoded compressed postscript file including three figures.
Carlsson, Mats, Stein, Robert F.
openaire   +2 more sources

Searching for Rotational X‐Ray Modulation on TIC 277539431

open access: yesAstronomische Nachrichten, Volume 347, Issue 3, March 2026.
ABSTRACT TIC 277539431, a fast rotating M7 dwarf, was detected to host the highest latitude flare to date at 81°$$ {81}^{{}^{\circ}} $$. Magnetic activity like stellar flares occurring at high latitude indicate occurrence of coronal loops at these latitudes on fully‐convective M dwarfs. In contrast, sunspots usually occur below 30°$$ {30}^{{}^{\circ}} $
Desmond Dsouza   +2 more
wiley   +1 more source

Extreme Red-wing Enhancements of UV Lines during the 2022 March 30 X1.3 Solar Flare

open access: yesThe Astrophysical Journal, 2023
Here, we present the study of a compact emission source during an X1.3 flare on 2022 March 30. Within a ∼41 s period (17:34:48 UT to 17:35:29 UT), Interface Region Imaging Spectrograph observations show spectral lines of Mg ii , C ii , and Si iv with ...
Yan Xu   +5 more
doaj   +1 more source

The mystery of the chromosphere [PDF]

open access: yes, 1996
We discuss many aspects of the solar chromosphere from an observational point of view, and show that most existing models are in direct contradiction to radio and eclipse measurements.
Zirin, Harold
core  

The chromosphere: gateway to the corona, or the purgatory of solar physics?

open access: yes, 2010
I argue that one should attempt to understand the solar chromosphere not only for its own sake, but also if one is interested in the physics of: the corona; astrophysical dynamos; space weather; partially ionized plasmas; heliospheric UV radiation; the ...
D. Biskamp   +13 more
core   +1 more source

Periodic Density Structures Observed in Ulysses Data: First Results

open access: yesJournal of Geophysical Research: Space Physics, Volume 131, Issue 3, March 2026.
Abstract Periodic density structures (PDSs) are advecting quasi‐periodic (periodicities between several minutes and several hours) density enhancements observed in the solar wind and corona. There is strong evidence that PDSs are formed at the Sun.
Brent M. Randol   +3 more
wiley   +1 more source

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