相关论文: Hydrogen Lyman emission through the solar cycle
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 solar radiation in the Lyman-alpha spectral line of hydrogen plays a significant role in the illumination of chromospheric and coronal structures, such as prominences, spicules, chromospheric fibrils, cores of coronal mass ejections,…
Aims: Out of a novel observing technique, we publish for the first time, SoHO-SUMER observations of the true spectral line profile of hydrogen Lyman-alpha in quiescent prominences. With SoHO not being in Earth orbit, our high-quality data…
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…
Recent observations of interplanetary medium (IPM) atomic hydrogen Lyman-{\alpha} (Ly{\alpha}) emission in the outer solar system, made with the Alice ultraviolet spectrograph on New Horizons (NH), are presented. The observations include…
The Lyman-alpha (Ly{\alpha};1216 {\AA}) line is the brightest emission line in the quiescent solar spectrum and radiates a significant fraction of the available nonthermal energy during flares. Despite its importance, there is a lack of…
We examine Saturn's non-auroral (dayglow) emissions at Lyman-$\alpha$ observed by the {Cassini/UVIS} instrument from 2004 until 2016, to constrain meridional and seasonal trends in the upper atmosphere. We separate viewing geometry effects…
The hydrogen Lyman-$\alpha$ (H {\sc i} Ly$\alpha$) emission during solar flares has rarely been studied in spatially resolved images and its physical origin has not been fully understood. In this paper, we present novel Ly$\alpha$ images…
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,…
This review summarizes our current understanding of the outer heliosphere and local interstellar medium (LISM) inferred from observations and modeling of interplanetary Lyman-$\alpha$ emission. The emission is produced by solar Lyman-alpha…
As the Lyman-alpha (Lya) line of neutral hydrogen is the brightest emission line in the solar spectrum, detecting increases in irradiance due to solar flares at this wavelength can be challenging due to the very high background. Previous…
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 present the first detection of solar flare emission at middle-ultraviolet wavelengths around 2000 A by the channel 2 of the Large-Yield RAdiometer (LYRA) onboard the PROBA2 mission. The flare (SOL20170906) was also observed in the…
Wilhelm et al. have recently called attention to the unidentified broad emission features near 117 nm in the solar spectrum. They discuss the observed properties of these features in detail but do not identify the source of this emission.…
We present some theoretical predictions concerning the amplitude and magnetic sensitivity of the linear polarization signals produced by scattering processes in the hydrogen Ly-alpha line of the solar transition region. To this end, we have…
The chromospheric Lyman-alpha line of neutral hydrogen (\lya; 1216\AA) is the strongest emission line in the solar spectrum. Fluctuations in \lya\ are known to drive changes in planetary atmospheres, although few instruments have had the…
There are very few reports of flare signatures in the solar irradiance at H i Lyman {\alpha} at 121.5 nm, i.e. the strongest line of the solar spectrum. The LYRA radiometer onboard PROBA2 has observed several flares for which unambiguous…
We analyze a series of full-Sun observations, which was performed with the SoHO/SUMER instrument between March and October 1996. Some parameters (radiance, shift and width) of the S VI 93.3 nm, S VI 94.4 nm, and Lyman Epsilon line profiles…
The Lyman alpha line is a robust tracer of high redshift galaxies. We present estimates of Lyman alpha emission from a protogalactic halo illuminated by UV background radiation fields with various intensities. For this purpose, we performed…
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…