Results 71 to 80 of about 5,203 (216)

Solar Spectroscopy and (Pseudo-)Diagnostics of the Solar Chromosphere [PDF]

, 2010
I first review trends in current solar spectrometry and then concentrate on comparing various spectroscopic diagnostics of the solar chromosphere. Some are actually not at all chromospheric but just photospheric or clapotispheric and do not convey ...
Raveendran, A.S.N., Chaudhuri, R.K., Astrophysics, Robert J. Rutten, Rutten, R.J., Dep Natuurkunde, Mekkaden, A.V.   +6 more
core   +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

Solar Activity Impacts on Ionospheric Scintillation and Precise Point Positioning Based on Multi‐Year GNSS and Scintillation Observations

Space Weather, Volume 24, Issue 3, March 2026.
Abstract Solar activity induces ionospheric irregularities that degrade Global Navigation Satellite System (GNSS) performance through amplitude and phase scintillation. Although numerous studies have investigated event‐driven or regional responses, the nonlinear coupling between solar radiation, ionospheric scintillation, and precise point positioning (
Jincheng Li, Qi Liu, Xiaomin Luo, Manuel Hernández‐Pajares, Enric Monte‐Moreno, Guangxia Wang, Heng Yang, Chuanding Zhang, Li Yang, Yaoyao Liu   +9 more
wiley   +1 more source

Alfvénic wave heating of the upper chromosphere in flares [PDF]

, 2016
We have developed a numerical model of flare heating due to the dissipation of Alfvénic waves propagating from the corona to the chromosphere. With this model, we present an investigation of the key parameters of these waves on the energy transport ...
Russell, A. J.B., Reep, J. W., Russell, A. J. B.   +2 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

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

Survival efficacy of chromosphere cell grafts.

, 2016
Survival efficacy of chromosphere cell grafts.
René Drucker-Colín (2950836), Marcela Palomero-Rivero (348126), Magdalena Guerra-Crespo (2950833), Alejandra Boronat-García (2950839), Diana Millán-Aldaco (348127)   +4 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

Pulsating chromosphere of classical Cepheids

, 2020
International audienceContext. It has recently been shown that the infrared (IR) emission of Cepheids, constant over the pulsation cycle, might be due to a pulsating shell of ionized gas with a radius of about 15% of that of the star radius, which could ...
Mérand, Antoine, Javanmardi, B., Gallenne, Alexandre, A. Chiavassa, Nardetto, N., Borgniet, S., Mérand, A., V. Hocdé, Lagadec, E., Hocdé, Vincent, Lagadec, Éric, Kervella, P., Hocdé, V., Chiavassa, Andrea, Evans, N., Nardetto, Nicolas, A. Mérand, Kervella, Pierre, P. Kervella, A. Gallenne, Breuval, L., E. Lagadec, D. Gillet, L. Breuval, N. Evans, Gillet, D., N. Nardetto, Ph. Mathias, Chiavassa, A., Mathias, Ph., B. Javanmardi, S. Borgniet, Gallenne, A.   +32 more
core   +1 more source