Related papers: Quiet-Sun hydrogen Lyman-alpha line profile derive…
Recent studies of interstellar neutral (ISN) hydrogen observed by the Interstellar Boundary Explorer (IBEX) suggested that the present understanding of the radiation pressure acting on hydrogen atoms in the heliosphere should be revised.…
The hydrogen Lyman-alpha plays a dominant role in the radiative energy transport in the lower transition region, and is important for the stud- ies of transition-region structure as well as solar wind origin. We investigate the Ly-alpha…
We present observations and results of radiance and irradiance studies completed by SoHO-SUMER during the past solar cycle. We find that the cycle variation in Ly-alpha irradiance as observed by e.g. UARS-SOLSTICE can not be explained by…
We investigate the formation of the H I Lyman-alpha and Lyman-beta lines in an equatorial coronal streamer. Particular attention is paid to frequency redistribution for the scattering of the incident radiation. The properties of the…
We present a modification of a model of solar cycle evolution of the solar Lyman-alpha line profile, along with a sensitivity study of interstellar neutral H hydrogen to uncertainties in radiation pressure level. The line profile model,…
Observations of the Sun's surface suggest a nonuniform radiated flux as related to the presence of bright active regions and darker coronal holes. The variations of the FUV/EUV source radiation can be expected to affect the Lyman-alpha…
The Chromospheric Lyman Alpha Spectropolarimeter (CLASP) observed the Sun in H I Lyman-{\alpha} during a suborbital rocket flight on September 3, 2015. The Interface Region Imaging Telescope (IRIS) coordinated with the CLASP observations…
We present a theoretical profile of the Lyman Beta line of atomic hydrogen perturbed by collisions with neutral hydrogen atoms and protons. We use a general unified theory in which the electric dipole moment varies during a collision. A…
We use state-of-the-art radiation-MHD simulations and 3D non-LTE radiative transfer computations to investigate \Halpha\ line formation in the solar chromosphere and apply the results of this investigation to develop the potential of…
We study the emission of the hydrogen Lyman-a line in the quiet Sun, its center-to-limb variation (CLV), and its radiance distribution. We also compare quasi-simultaneous Ly-a and Ly-b line profiles. We used the high spectral and spatial…
We study the influence of the non-flat shape of the solar Lyman-alpha line on the distribution of neutral interstellar hydrogen in the inner heliosphere and assess importance of this effect for interpretation of heliospheric in situ…
The linear polarization produced by scattering processes in the hydrogen Lyman alpha line of the solar disk radiation is a key observable for probing the chromosphere-corona transition region (TR) and the underlying chromospheric plasma.…
Accurately measuring and modeling the Lyman-$\alpha$ (Ly$\alpha$; $\lambda$1215.67 \AA) emission line from low mass stars is vital for our ability to build predictive high energy stellar spectra, yet interstellar medium (ISM) absorption of…
The determination of solar wind outflow velocity is fundamental in order to probe the mechanisms of wind acceleration in the corona. We aim to study, via the Doppler dimming technique, the effects that the chromospheric Ly{\alpha} line…
The Lyman-alpha emission line dominates the far-ultraviolet spectra of late-type stars and is a major source for photodissociation of important molecules including H2O, CH4, and CO2 in exoplanet atmospheres. The incident flux in this line…
The hydrogen Lyman lines ( 91.2 nm < lambda < 121.6 nm) are significant contributors to the radiative losses of the solar chromosphere, and are enhanced during flares. We have shown previously that the Lyman lines observed by the Extreme…
There is a thin transition region (TR) in the solar atmosphere where the temperature rises from 10,000 K in the chromosphere to millions of degrees in the corona. Little is known about the mechanisms that dominate this enigmatic region…
Broad sets of spectroscopic observations comprising multiple lines represent an excellent opportunity for diagnostics of the properties of the prominence plasma and the dynamics of their fine structures. However, they also bring significant…
We propose to infer ionising continuum leaking properties of galaxies by looking at their Lyman-alpha line profiles. We carry out Lyman-alpha radiation transfer calculations in two models of HII regions which are porous to ionising…
We study the capabilities of Lyman $\beta$ and the O I 1027 and 1028 \AA\ spectral lines for understanding the properties of the chromosphere and transition region. The oxygen transitions are located in the wing of Lyman $\beta$ that is a…