Results 41 to 50 of about 860 (219)

The Chromospheric Activity and Variability of Cycling and Flat Activity Solar‐Analog Stars

The Astrophysical Journal, 2004
We present an analysis of more than 3700 observations of the Ca II H and K lines in 57 Sun-like stars and over 3000 analogous observations of the Sun. Ten of the 57 stars under consideration are observed in flat states, but these stars do not always exhibit overall Ca II H and K core brightness below that of solar minimum.
Jeffrey C. Hall, G. W. Lockwood
openaire   +1 more source

Investigating Alfvénic wave propagation in coronal open-field regions

, 2015
The physical mechanisms behind accelerating solar and stellar winds are a long-standing astrophysical mystery, although recent breakthroughs have come from models invoking the turbulent dissipation of Alfvén waves.
Morton, Richard, Tomczyk, Steve, Pinto, Rui   +2 more
core   +1 more source

Advancing Heliophysics and Space Weather Modeling Through Open Science

Space Weather, Volume 24, Issue 6, June 2026.
Abstract We present a community‐wide effort to develop a strategy and action plan to advance heliophysics and space weather modeling through open science. While open science has the potential to enhance the quality and pace of scientific discovery, its application to scientific modeling requires more careful consideration regarding open data and open ...
C. Corti, M. M. Kuznetsova, M. A. Reiss, J. Yue, J. Karpen, C. N. Arge, F. Bacchini, C. Bard, S. Bruinsma, R. M. Caplan, L. K. S. Daldorff, P. J. Deka, C. R. DeVore, S. Elvidge, N. Ganushkina, J. D. Huba, B. V. Jackson, V. Jordanova, J. A. Linker, H. Liu, J. G. Luhmann, S. Markidis, P. Mayank, V. Merkin, N. Moens, D. Odstrcil, Y. A. Omelchenko, M. Palmroth, S. Poedts, A. J. Ridley, Y. Shou, V. Tenishev, D. R. Themens, G. Toth, W. Wang, R.‐P. Wilhelm, M. A. Young, B. Cecconi, M.‐Y. Chou, D. De Zeeuw, G. L. Delzanno, C. Didigu, M. El Alaoui, S. Fung, J. Green, Z. Huang, L. K. Jian, L. J. Landwer, M. Lesko, P. MacNeice, A. Masson, M. L. Mays, P. M. Mehta, M. S. Miesch, E. Palmerio, M. Petrenko, E. Provornikova, L. Rastätter, L. Rusaitis, N. Sachdeva, E. Samara, D. Sur, A. Taktakishvili, J. Topper, T. Tsui, C. Verbeke, J. Wang, C. Wiegand, M. Wiltberger, Y. Zheng, M. M. Bisi, M. K. Georgoulis, T. Kodikara, T. Pulkkinen, A. Chartier, D. da Silva, A. Faturahman, K. Garcia‐Sage, D. Kondrashov, V. E. Ledvina, W. Liu, C. Pandey, E. Resnick, C. Shi, R. S. Weigel, K. Whitman, I. Zakharenkova, K. Zhang   +87 more
wiley   +1 more source

Construction of a century solar chromosphere data set for solar activity related research

Solar-Terrestrial Physics, 2017
This article introduces our ongoing project “Construction of a Century Solar Chromosphere Data Set for Solar Activity Related Research”. Solar activities are the major sources of space weather that affects human lives. Some of the serious space weather consequences, for instance, include interruption of space communication and navigation, compromising ...
Ganghua Lin, Xiao Fan Wang, Xiao Yang, Suo Liu, Mei Zhang, Haimin Wang, Chang Liu, Yan Xu, Tlatov A.G., Demidov M.L., Borovik A.V., Golovko A.A.   +11 more
openaire   +4 more sources

THE KINEMATICS AND PLASMA PROPERTIES OF A SOLAR SURGE TRIGGERED BY CHROMOSPHERIC ACTIVITY IN AR11271 [PDF]

The Astrophysical Journal, 2012
We observe a solar surge in NOAA AR11271 using the Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly 304 A image data on 2011 August 25. The surge rises vertically from its origin up to a height of ≈65 Mm with a terminal velocity of ≈100 km s–1, and thereafter falls and fades gradually. The total lifetime of the surge was ≈20 minutes.
P. Kayshap, Abhishek K. Srivastava, K. Murawski   +2 more
openaire   +1 more source

The influence of the magnetic field on running penumbral waves in the solar chromosphere

, 2013
We use images of high spatial and temporal resolution, obtained using both ground- and space-based instrumentation, to investigate the role magnetic field inclination angles play in the propagation characteristics of running penumbral waves in the solar ...
Jess, D.B.; id_orcid, Van Doorsselaere, T., Reznikova, V, Keys, P. H.; id_orcid, Mackay, D.H., Reznikova, Veronika, Mackay, Duncan Hendry, Keys, P.H., Jess, David, Keys, Peter, Reznikova, V. E., Van Doorsselaere, Tom, MacKay, D. H.   +12 more
core   +1 more source

The Formation Height of Millimeter-wavelength Emission in the Solar Chromosphere

, 2020
In the past few years, the ALMA radio telescope has become available for solar observations. ALMA diagnostics of the solar atmosphere are of high interest because of the theoretically expected linear relationship between the brightness temperature at ...
Martínez-Sykora, Juan, Rodriguez, Jaime de la Cruz,, Chintzoglou, Georgios, De Pontieu, Bart   +3 more
core   +1 more source

Magnetic Coupling of the Active Chromosphere to the Solar Interior

The Astrophysical Journal, 1972
Evidence is summarized to show that the configuration of e lines which governs the appearance of H-alpha fine structure in active regions is set mainly by motions in the subphotosphere where these lines are anchored. It is shown that H-alpha fine structure is directly coupled to a layer probably more than 5000 km below the photosphere, and little ...
openaire   +1 more source

Spectral Irradiance Observations and Projections for Solar Cycle 25

Earth and Space Science, Volume 13, Issue 4, April 2026.
Abstract The Ozone Monitoring Instrument (OMI) on the Aura satellite makes near‐daily measurements of solar spectral irradiance (SSI) at wavelengths between 265 and 500 nm for instrument calibration purposes. The low degradation and exceptional stability of OMI's calibration during its lifetime facilitates the creation of a new 18‐year OMI Version 7 ...
Matthew T. DeLand, Sergey V. Marchenko, Judith L. Lean, Odele Coddington   +3 more
wiley   +1 more source

Reconstructing Historical Solar Indices for Predicting Past Space Weather Events

Space 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, Denny M. Oliveira, Theodosios Chatzistergos, Gangkai Poh, Eftyhia Zesta   +4 more
wiley   +1 more source