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Article
Open AccessOn the Physical Nature of the so-Called Prominence Tornadoes
The term ‘tornado’ has been used in recent years to describe several solar phenomena, from large-scale eruptive prominences to small-scale photospheric vortices. It has also been applied to the generally stabl...
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Article
Open AccessSolar Ultraviolet Bursts
The term “ultraviolet (UV) burst” is introduced to describe small, intense, transient brightenings in ultraviolet images of solar active regions. We inventorize their properties and provide a definition based ...
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Article
Václav Bumba (1925 – 2018)
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Article
Observed IRIS Profiles of the h and k Doublet of Mg ii and Comparison with Profiles from Quiescent Prominence NLTE Models
With the launch of the Interface Region Imaging Spectrograph (IRIS) mission, it is now possible to obtain high-resolution solar prominence spectra and to begin to distinguish the contributions of the many (appare...
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Chapter
Radiative Transfer in Solar Prominences
Critical information about prominence physical conditions can be obtained only by analyzing prominence spectra or high-resolution monochromatic images. Solar prominences are low-density structures and, therefo...
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Article
Multi-wavelength study of a high-latitude EUV filament
A large filament was observed during a multi-wavelength coordinated campaign on June 19, 1998 in the Hα line with the Swedish Vacuum Solar Telescope (SVST) at La Palma, in the coronal lines Fe ix/x 171 Å and F...
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Chapter
Transport of Energy from the Corona to the Chromosphere During Flares
Hard X-ray (HXR) observations frequently exhibit fast temporal variations during the impulsive phase of solar fiares and this is usually ascribed to the propagation of beams of accelerated particles and to the...
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Article
OPTICAL AND RADIO SPECTRAL ANALYSIS OF A RECURRENT SURGE
Coordinated observations obtained at Meudon (MSDP) and at Ondřejov provide surge spectra in optical range (Hα, Hβ, Hγ, Hµ, Ca H and K lines) and in radio range. The MSDP data allowed us to follow the time evol...
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Article
On the nature of bright rims of filaments
A filament with a very bright rim was observed in the Hα line on May 11, 1989, using the Meudon spectroheliograph. Absolute calibration of the spectroheliogram allows us to express the intensities in particular s...
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Article
On the occurrence of blue asymmetry in chromospheric flare spectra
We present observations of optical spectra of a flare in which blue line asymmetry was seen for more than 4 min close to the flare onset. The maximum blue asymmetry coincided with the maximum of a hard X-ray a...
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Chapter
Fine Structures of the Solar Chromosphere
We summarize studies of the spatial and temporal behavior of the physical parameters of the chromospheric fine structures called mottles (or disk spicules), using high spatial resolution observations obtained ...
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Article
A chromospheric response to pulse beam heating
Starting from the new flare models of Karlický (1990) and Karlický and Hénoux (1991), we present here the first time-dependent numerical simulations of hydrogen plasma excitation and ionization on time scales ...
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Chapter and Conference Paper
HYdrogen line formation in filamentary prominences
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Article
Book review
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Chapter
Partial Redistribution Interlocking in the Solar Chromosphere
Starting with the model of a quiet solar chrcmosphere, we have calculated the relative probabilities of radiative and natural population of the second and third hydrogen levels, pertinent to various population...
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Chapter
Redistribution Functions: A Review of Computational Methods
In the present paper, we review and compare the existing computational methods developed to evaluate various types of redistribution functions applicable in astrophysics. We discuss in detail several numerical...
