Results 31 to 40 of about 513 (133)

Periodic Density Structures Observed in Ulysses Data: First Results

Journal 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, Nicholeen Viall, Larry Kepko, Simone Di Matteo   +3 more
wiley   +1 more source

On the Freeze‐In Distance of Solar Wind Fluid Entropy Variability in the Corona

Journal of Geophysical Research: Space Physics, Volume 131, Issue 3, March 2026.
Abstract The strong correlation between solar wind entropy and the frozen‐in ion charge state ratio O7+/O6+ ${\mathrm{O}}^{7+}/{\mathrm{O}}^{6+}$ indicates that entropy variability on timescales of hours or longer is preserved from its solar source. This prompts the question: where in the solar atmosphere does this entropy variability come from, and at
Aidan J. Nakhleh, Nicholeen M. Viall, Susan T. Lepri, Jim M. Raines   +3 more
wiley   +1 more source

A New Method for Probabilistic Spatiotemporal Forecasts of Solar Soft X‐Ray “S‐Class” (>X10) Superflares

Journal of Geophysical Research: Space Physics, Volume 131, Issue 2, February 2026.
Abstract Solar superflares of S‐class (>X10 in soft X‐rays) pose extreme space weather hazards, yet their prediction remains a fundamental challenge owing to their rapid and transient natures and the limitations of conventional event‐based forecasts. We introduce for the first time, a probabilistic spatiotemporal framework designed to identify extended
V. M. Velasco Herrera, G. Velasco Herrera, W. Soon, A. Özgüç, N. Babynets, A. Tlatov, M. Švanda, S. Qiu, S. Baliunas, B. Kotan, G. González González, L. A. Bautista Flores, M. Pazos   +12 more
wiley   +1 more source

Photospheric Magnetic Field of the Sun: Two Patterns of the Longitudinal Distribution

Solar Physics, 2007
14 pages, 5 figures, 1 table; submitted to Solar Physics; 2 figures ...
Vernova, E. S., Tyasto, M. I., Baranov, D. G.   +2 more
openaire   +2 more sources

Mapping the Sun's upper photosphere with artificial neural networks

, 2021
We have developed an inversion procedure designed for high-resolution solar spectro-polarimeters, such as Hinode/SP or DKIST/ViSP. The procedure is based on artificial neural networks trained with profiles generated from random atmospheric stratifications for a high generalization capability. When applied to Hinode data we find a hot fine-scale network
Socas-Navarro, Hector, Ramos, Andres Asensio   +1 more
openaire   +2 more sources

Addressing Known Challenges in Solar Flare Forecasting I: Limb‐Flare Prediction With a 4π Full‐Heliosphere Framework

Space Weather, Volume 24, Issue 2, February 2026.
Abstract A demonstrated failure mode for operational solar flare forecasting is the inability to forecast flares that occur near, or just beyond, the solar limb. To address this shortcoming, we develop a “4π $4{\uppi }$” full‐heliosphere event forecasting framework and evaluate its statistical classification ability against this specific challenge.
K. D. Leka, Eric L. Wagner, Lisa Upton, Bibhuti Kumar Jha, Kiran Jain, Sara Petty   +5 more
wiley   +1 more source

Kinetic Modeling of Inertial Alfvén Waves in the Solar Corona: Implications for Heating and Particle Acceleration

Journal of Geophysical Research: Space Physics, Volume 131, Issue 1, January 2026.
Abstract Recent observations from Parker Solar Probe and Solar Orbiter highlight the importance of Alfvén waves in solar coronal heating and particle acceleration. In this study, we investigate inertial Alfvén waves (IAWs), which operate at electron inertial scales, as a potential mechanism for plasma heating and charged particle acceleration in the ...
S. Ayaz, Gary P. Zank, Imran A. Khan, Andreas Shalchi, L.‐L. Zhao, Yeimy J. Rivera   +5 more
wiley   +1 more source

Stratigraphy of Carbonate‐Bearing Rocks at the Margin of Jezero Crater, Mars: Evidence for Shoreline Processes?

Journal of Geophysical Research: Planets, Volume 131, Issue 1, January 2026.
Abstract Martian carbonate‐bearing rocks are compelling targets for exploration because they preserve detailed records of past aqueous processes, climate, and habitability. The Margin unit in Jezero crater is a distinct olivine‐ and carbonate‐bearing unit stratigraphically underlying the western fan, lining the inner margin of the western crater rim ...
Alexander J. Jones, Sanjeev Gupta, Robert Barnes, Briony H. N. Horgan, Kenneth H. Williford, Gerhard Paar, Kathryn. M. Stack, Bradley J. Garzcynski, Eleni Ravanis, Candice C. Bedford, Justin I. Simon, Athanasios Klidaras, Linda C. Kah, James F. Bell, Justin Maki, Stephen W. Lokier, Adrian Brown, Nathan R. Williams, Sanna Alwmark, Jorge I. Núñez, Fred Calef, Larry Crumpler, Alicia Vaughan, Libby R. W. Ives, Sam Gwizd, Ken Farley, Christian Tate, Nicolas Randazzo, Olivier Beyssac, Gwénaël Caravaca   +29 more
wiley   +1 more source

Statistical equilibrium and photospheric abundance of silicon in the Sun and in Vega [PDF]

Astronomy & Astrophysics, 2001
Based on detailed non-LTE calculations, an updated determination of the abundance of silicon in the Sun and Vega is presented. The model atom includes neutral and singly ionized stages of silicon with 115 energy levels and 84 line transitions. Non-LTE eects are found to be quite small in the Sun.
openaire   +1 more source

Тhе telescope for observation of the photosphere of the Sun [PDF]

Bulletin of Taras Shevchenko National University of Kyiv. Astronomy, 2015
V. Efimenko, S. Kaminsky
openaire   +1 more source