Results 21 to 30 of about 5,669 (225)
International Astronomical Union Colloquium, 1980 Important progress in our understanding of stellar chromospheres has occurred in the past few years as a result of new observations, developments in spectral line formation theory, and the application of that theory to the construction of detailed model chromospheres.
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Earth and Space Science, 2020 Solar prominences are structures of importance because of their role in polar field reversal. We study the long‐term variation of the time latitude distribution of solar prominences in this article.
Subhamoy Chatterjee +4 more
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Open Astronomy, 2021 We present intensity curves of solar flares obtained in the Hα hydrogen line and CaII H, CaIR 8542Å lines using multichannel spectrographs of Ondřejov Observatory (Czech Republic) for the period 2000–2012.
Kupryakov Yurij Alekseevich +5 more
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Chromospheric Seismology [PDF]
Symposium - International Astronomical Union, 1988 The aim of the present study is to examine whether seismologic diagnostic techniques may be used to improve the models of the solar chromosphere. We are mainly concerned by oscillations observed in the cores of strong lines such as the resonance lines of Ca II or Mg II. It is intuitive, and confirmed by numerical simulations (Gouttebroze and Leibacher,
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Inferring depth-dependent plasma motions from surface observations using the DeepVel neural network
Journal of Space Weather and Space Climate, 2021 Coverage of plasma motions is limited to the line-of-sight component at the Sun’s surface. Multiple tracking and inversion methods were developed to infer the transverse motions from observational data.
Tremblay Benoit +4 more
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Subarcsecond Imaging of a Solar Active Region Filament With ALMA and IRIS
Frontiers in Astronomy and Space Sciences, 2022 Quiescent filaments appear as absorption features on the solar disk when observed in chromospheric lines and at continuum wavelengths in the millimeter (mm) range. Active region (AR) filaments are their small-scale, low-altitude analogues, but they could
J. M. da Silva Santos +6 more
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, 1994 We show results from SO/Sacramento Peak data to discuss three issues: (i)--the spatial occurrence of chromospheric 3--min oscillations; (ii)--the validity of Ca II H&K line-center Doppler Shift measurements; (iii)--the signi ?cance of oscillation power and phase at frequencies above 10 mHz.
Lites, B.W., Rutten, R.J., Thomas, J.H.
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Journal of Space Weather and Space Climate, 2020 We present the observing program proposed by Paris and Côte d’Azur Observatories for monitoring solar activity during the upcoming cycle 25 and providing near real time images and movies of the chromosphere for space-weather research and applications ...
Malherbe Jean-Marie +2 more
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An ALMA Observation of Time Variations in Chromospheric Temperature of a Solar Plage Region
Frontiers in Astronomy and Space Sciences, 2022 Nanoflares and the shock formation of magnetohydrodynamic waves in the solar chromosphere have been considered as key physical mechanisms of the heating of the chromosphere and corona.
Masashi Abe +5 more
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Solar-Terrestrial Physics, 2020 We have studied two regions located at the base of a coronal hole. For the K₁ intensity minima and K₂ peaks, which form between the upper photosphere and the lower chromosphere and in the lower chromosphere respectively, a number of Ca II line parameters
I.P. Turova +2 more
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