Results 71 to 80 of about 1,010,043 (218)

Observations of the upper solar chromosphere with SUMER

, 2003
The structure and dynamics of the solar chromosphere are still matters of debate. The chromospheric network reflecting the supergranulation of the outer convection zone of the Sun is a prominent feature of the lower solar atmosphere that extends into the
Kalkofen, W., K. Wilhelm, Wilhelm, K., W. Kalkofen   +3 more
core   +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

Space Weather Impact of Three Solar Flares Observed by the POEMAS Telescope at 45 and 90 GHz

Journal of Geophysical Research: Space Physics, Volume 130, Issue 11, November 2025.
Abstract Solar flares are often associated with coronal mass ejections (CMEs) that, when directed toward Earth, can disrupt the magnetosphere and impact space weather. In this study, we investigate three long‐duration solar flares observed in 2012 by the POlarization Emission of Millimeter Activity at the Sun (POEMAS) telescopes at 45 and 90 GHz.
Adriana Valio, Karla F. Lopez, José Luis Gamonal Valenzuela, Ruben M. Romero Ramírez, Dougas F. da Silva   +4 more
wiley   +1 more source

Formation of the Lyman Continuum during Solar Flares

The Astrophysical Journal, 2023
The Lyman continuum (LyC;
Shaun A. McLaughlin, Ryan O. Milligan, Graham S. Kerr, Aaron J. Monson, Paulo J. A. Simões, Mihalis Mathioudakis   +5 more
doaj   +1 more source

Solar Flare Activity, 1937–2024: Introducing the New Hemispheric Solar Flare Index (hSFI) in the Context of 2024's Major Solar Storm Events

Space Weather, Volume 23, Issue 11, November 2025.
Abstract A new daily composite of the solar flare index (SFI) and the hemispherically‐resolved versions (hSFI) are presented for 1937 to 2024. The data set confirms that the northern hemisphere (NH) dominated solar flare activity during Solar Cycles 17 to 21, but that the southern hemisphere has dominated from Solar Cycle 22 to present.
V. M. Velasco Herrera, W. Soon, S. Knoška, A. Özgüç, G. Velasco Herrera, H. Yeşilyaprak, N. Babynets, M. Švanda, J. Muraközy, S. Qiu, D. Riveros‐Rosas, R. Connolly, M. Connolly, A. Tlatov, L. Cappellotto   +14 more
wiley   +1 more source

Heating of the quiet solar chromosphere [PDF]

Solar Physics, 1994
We have analyzed a large number of Caii H line profiles at the sites of the bright points in the interior of the network using a 35-min-long time sequence of spectra obtained at the Vacuum Tower Telescope (VTT) of the Sacramento Peak Observatory on a quiet regon of the solar disc and studied the dynamical processes associated with these structures. Our
Kariyappa, R., Sivaraman, K.R., Anadaram, M.N.   +2 more
openaire   +2 more sources

The emergence of magnetic flux through a partially ionised solar atmosphere [PDF]

, 2006
We present results from 2.5D numerical simulations of the emergence of magnetic flux from the upper convection zone through the photosphere and chromosphere into the corona. Certain regions of the solar atmosphere are at sufficiently low temperatures to be
J. E. Leake, T. D. Arber, Leake, J. E. (James E.), Arber, T. D.   +3 more
core   +1 more source

Solar Radio Wide‐Band Spectroscopy and Imaging Facilities of the Chinese Meridian Project Phase II

Space Weather, Volume 23, Issue 11, November 2025.
Abstract Solar eruptions, including flares and coronal mass ejections, are the most energetic phenomena in the solar system. These explosive events accelerate high‐energy particles and generate electromagnetic radiation from radio to gamma‐ray wavelengths, producing heliospheric disturbances and acting as primary drivers of space weather hazards.
Yihua Yan, Wei Wang, Linjie Chen, Jin Fan, Yao Chen, Shuwang Chang, Fabao Yan, Lihong Geng, Sha Li, Cang Su, Zhijun Chen, Chengming Tan, Bing Wang, Guang Lu, Chuanyang Li, Zhichao Zhou, Fei Liu, Suli Ma, Jun Cheng, Jing Du   +19 more
wiley   +1 more source

Three-dimensional numerical experiments on granulation-generated, two-fluid waves and flows in a solar magnetic carpet

Astronomy & Astrophysics
Context. These studies were carried out in the context of solar-chromosphere heating and solar-wind generation. Aims. We aim to explore granulation-generated, two-fluid waves and flows in the solar atmosphere permeated by a solar magnetic carpet. Methods.
Niedziela R., Murawski K., Wołoszkiewicz P.   +2 more
doaj   +1 more source

Dominant Trends in Jupiter's H3+ ${\mathbf{H}}_{\mathbf{3}}^{\mathbf{+}}$ Northern Aurora: II. Magnetospheric Mapping

Journal of Geophysical Research: Space Physics, Volume 130, Issue 10, October 2025.
Abstract Jupiter's auroral regions have previously been defined by broad‐scale auroral structures, but these are typically obscured by the wide array of temporal variability observed at timescales between minutes and days, making it difficult to understand the underlying magnetospheric biases driving these brightness differences.
Tom S. Stallard, Katie L. Knowles, Henrik Melin, Ruoyan Wang, Emma M. Thomas, Luke Moore, James O’Donoghue, Rosie E. Johnson, Steve Miller, John C. Coxon   +9 more
wiley   +1 more source