Results 101 to 110 of about 15,079 (225)

On the origin of the magnetic energy in the quiet solar chromosphere

, 2019
The presence of magnetic field is crucial in the transport of energy through the solar atmosphere. Recent ground-based and space-borne observations of the quiet Sun have revealed that magnetic field accumulates at photospheric heights, via a local dynamo
Carlsson, Mats, De Pontieu, Bart, Gosic, Milan, Gudiksen, Boris, Hansteen, Viggo H., Martínez-Sykora, Juan   +5 more
core   +1 more source

Robust Statistical Techniques for Operational Maintenance of the 10.7 cm Solar Radio Flux

Space Weather, Volume 23, Issue 5, May 2025.
Abstract The F10.7 solar radio flux is a critical quantity for operational space weather nowcasting and forecasting, where it is routinely used as a driver for coupled atmospheric models to estimate a variety of important quantities such as the neutral atmospheric density.
Daniel A. Brandt, Erick F. Vega, Brian J. Thelen   +2 more
wiley   +1 more source

The quiet chromosphere. Old wisdom, new insights, future needs

, 2010
The introduction to this review summarizes chromosphere observation in two figures. The first part showcases the historical emphasis on the eclipse chromosphere in the development of NLTE line formation theory and criticizes 1D modeling.
Rutten, Robert J.
core  

Small-scale structure and dynamics of the lower solar atmosphere

, 2007
The chromosphere of the quiet Sun is a highly intermittent and dynamic phenomenon. Three-dimensional radiation (magneto-)hydrodynamic simulations exhibit a mesh-like pattern of hot shock fronts and cool expanding post-shock regions in the sub-canopy part
Avrett, Cauzzi, Friedrich Wöger, Kalkofen, Langangen, Leenaarts, Leenaarts, Sven Wedemeyer-Böhm, Tritschler, Wedemeyer, Wedemeyer-Böhm, Wilhelm, Wöger   +12 more
core   +1 more source

Atmospheric Heating and Wind Acceleration: Results for Cool Evolved Stars based on Proposed Processes

, 2014
A chromosphere is a universal attribute of stars of spectral type later than ~F5. Evolved (K and M) giants and supergiants (including the zeta Aurigae binaries) show extended and highly turbulent chromospheres, which develop into slow massive winds.
A. Brown, A. Chiavassa, A. Lobel, A. Lébre, A. Skumanich, A.D. McMurry, A.K. Dupree, B. Buchholz, B. Freytag, B. Pontieu De, B. Pontieu De, B. Pontieu De, B.E. Wood, C.-H. An, C.J. Schrijver, C.J. Schrijver, D. Fawzy, D. Rabin, D. Reimers, D.E. Osterbrock, D.F. Gray, D.J. Mullan, F.P. Pijpers, G.A. Gary, G.M. Harper, G.M. Harper, G.M. Harper, H. Alfvén, H. Peter, H. Peter, I. Pagano, J. Martínez-Sykora, J. Tu, J.A. Eaton, J.A. Eaton, J.D. Jackson, J.E. Leake, J.E. Leake, J.E. Leake, J.E. Leake, J.E. Vernazza, J.E. Vernazza, J.G. Doyle, J.G. Doyle, J.H. Piddington, J.L. Linsky, J.L. Linsky, J.M. Davila, J.M. Fontenla, J.M. Fontenla, J.V. Hollweg, J.V. Hollweg, K. Eriksson, K. Ohnaka, K.-P. Schröder, K.B. MacGregor, K.G. Carpenter, K.G. Carpenter, K.G. Carpenter, K.G. Carpenter, K.G. Strassmeier, L. Hartmann, L. Hartmann, L. Ofman, L. Ofman, L.S. Anderson, M. Auriére, M. Cuntz, M. Cuntz, M. Cuntz, M. Cuntz, M. Cuntz, M. Cuntz, M. Heinemann, M. Mathioudakis, M. Mitchner, M. Velli, M.C.M. Cheung, M.I. Pérez Martínez, M.L. Goodman, M.L. Goodman, M.L. Goodman, M.L. Khodachenko, M.R. Barkhudarov, M.S. Ruderman, N. Guerreiro, P. Charbonneau, P. Petit, P. Song, P. Ulmschneider, P. Ulmschneider, P.G. Judge, P.G. Judge, P.G. Judge, P.G. Judge, P.K. Shukla, R. Grappin, R. Lundin, R. Rosner, R. Rosner, R. Soler, R.A. Kopp, R.D. Robinson, R.G.M. Rutten, R.J. Morton, R.J. Morton, R.K. Konstantinova-Antova, R.K. Konstantinova-Antova, R.W Noyes, S. Tomczyk, S.B.F. Dorch, S.I. Braginskii, S.R. Cranmer, S.R. Cranmer, S.R. Cranmer, S.R. Cranmer, T. Simon, T. Tsuji, T.D. Arber, T.E. Holzer, T.K. Suzuki, T.K. Suzuki, T.K. Suzuki, T.R. Ayres, T.R. Ayres, T.R. Ayres, T.R. Ayres, U. Narain, U. Narain, U. Torkelsson, V. Hansteen, V. Krasnoselskikh, V.H. Hansteen, V.S. Airapetian, V.S. Airapetian, V.S. Airapetian, W.C. Danchi, W.H. Matthaeus, Y.-T. Lau, Z.E. Musielak   +139 more
core   +1 more source

Magnetic fields of an active region filament from full Stokes analysis of Si I 1082.7 nm and He I 1083.0 nm

, 2012
Vector magnetic fields of an active region filament in the photosphere and upper chromosphere are obtained from spectro-polarimetric observations recorded with the Tenerife Infrared Polarimeter (TIP II) at the German Vacuum Tower Telescope (VTT).
A. Lagg, Asensio Ramos, Canou, Centeno, Collados, Georgoulis, Guo, Harvey, Kurucz, Lagg, Leroy, Lin, Lites, Lites, López Ariste, Merenda, Okamoto, Paletou, Rüedi, S. Solanki, Sasso, Socas-Navarro, Solanki, Trujillo Bueno, Wang, Y. Liu, Z. Xu   +26 more
core   +1 more source

Chromospheric and Coronal Spectra [PDF]

Highlights of Astronomy, 1995
The interpretation of chromospheric and coronal spectra requires accurate ionization and recombination rates, collision strengths and transition probabilities. Recent projects to improve calculations of opacities in stellar interiors have led to a large amount of new atomic data.
openaire   +3 more sources

Inter-network regions of the Sun at millimetre wavelengths

, 2007
The continuum intensity at wavelengths around 1 mm provides an excellent way to probe the solar chromosphere. Future high-resolution millimetre arrays, such as the Atacama Large Millimeter Array (ALMA), will thus produce valuable input for the ongoing ...
Al, Ayres, B. Freytag, Bastian, Beasley, Brown, Carlsson, Carlsson, Conway, Escoffier, Fontenla, Freytag, H. G. Ludwig, J. Leenaarts, Krijger, Leenaarts, Loukitcheva, Loukitcheva, M. Steffen, S. Wedemeyer-Böhm, Tritschler, Uitenbroek, Vecchio, Wedemeyer, White, Wöger   +25 more
core   +3 more sources

Torsional Alfv\'en waves in solar partially ionized plasma: effects of neutral helium and stratification

, 2013
Ion-neutral collisions may lead to the damping of Alfven waves in chromospheric and prominence plasmas. Neutral helium atoms enhance the damping in certain temperature interval, where the ratio of neutral helium and neutral hydrogen atoms is increased ...
Khodachenko, M. L., Soler, R., Zaqarashvili, T. V.   +2 more
core   +1 more source

Stellar model chromospheres. IX - Chromospheric activity in dwarf stars

The Astrophysical Journal, 1979
High-resolution Ca II K line profiles are used to model the upper photospheres and lower chromospheres of eight main-sequence stars ranging in spectral type from F0 to M0 and exhibiting different degrees of chromospheric activity. The model chromospheres are studied as a function of spectral type and activity for stars of similar spectral type in order
W. L. Kelch, S. P. Worden, J. L. Linsky
openaire   +1 more source