相关论文: Coronal Diagnostics from Narrowband Images around …
We review the coronal visible and infrared lines, collecting previous observations, and comparing, whenever available, observed radiances with those predicted by various models: the quiet Sun, a moderately active Sun, and an active region…
For the first time, we present and discuss EUV radiances of the solar transition region (TR) and corona obtained during a solar cycle. The measurements were obtained with the SOHO/coronal diagnostic spectrometer (CDS) during the period from…
Most observations of the solar corona beyond 2 Rs consist of broadband visible light imagery from coronagraphs. The associated diagnostics mainly consist of kinematics and derivations of the electron number density. While the measurement of…
We report commissioning observations of the Si X 1430 nm solar coronal line observed coronagraphically with the Cryogenic Near-Infrared Spectropolarimeter (Cryo-NIRSP) at the National Science Foundation's Daniel K. Inouye Solar Telescope…
Measurements of the temperature and density structure of the solar corona provide critical constraints on theories of coronal heating. Unfortunately, the complexity of the solar atmosphere, observational uncertainties, and the limitations…
The profiles of emission lines formed in the corona contain information on the dynamics and the heating of the hot plasma. Only recently has data with sufficiently high spectral resolution become available for investigating the details of…
Alfven waves and ion-cyclotron absorption of high-frequency waves are frequently brought into models devoted to coronal heating and fast solar-wind acceleration. Signatures of ion-cyclotron resonance have already been observed in situ in…
We report on observations of a solar prominence obtained on 26 April 2007 using the Extreme Ultraviolet Imaging Spectrometer on Hinode. Several regions within the prominence are identified for further analysis. Selected profiles for lines…
There is a pressing need to model X-ray Ultra-Violet (XUV: 1-30 nm) stellar irradiances, given the scarcity of current measurements. One of the measurable effects of a stellar cycle is the significant (more than one order of magnitude)…
We present new images of the coronal line region, as traced by [Si VII] 2.48 \um, in some of the nearest Seyfert 2 galaxies. In each of these galaxies, the coronal line emission comprises a bright, compact central source and extended…
We present estimates of the signal to be expected in quiescent solar conditions, as would be obtained with the COronal Spectrographic Imager in the EUV in its coronagraphic mode (COSIE-C). COSIE-C has been proposed to routinely observe the…
It is generally accepted that densities of quiet sun and active region plasma are sufficiently low to justify the optically thin approximation, and it is commonly used in the analysis of line emissions from plasma in the solar corona.…
Accurate measurements of electron density are critical for determination of the plasma properties in the solar corona. We compare the electron densities diagnosed from Fe XIII lines observed by the Extreme-Ultraviolet Imaging Spectrometer…
Aims. To determine the solar transition region and coronal radius at EUV wavelengths and its time evolution during Solar Cycle XXIII. Methods. We use daily 30.4 and 17.1 nm images obtained by the Extreme Ultraviolet Imager (EIT) aboard the…
{The \ion{Na}{x} X-ray lines between 10.9 and 11.2~\AA\ have attracted little attention but are of interest since they enable an estimate of the coronal abundance of Na to be made. This is of great interest in the continuing debate on the…
The present solar cycle is particular in many aspects: it had a delayed rising phase, it is the weakest of the last 100 years, and it presents two peaks separated by more than one year. To understand the impact of these characteristics on…
We conduct the first systematic survey of a comprehensive set of the twenty optical coronal lines in the spectra of nearly 1 million galaxies observed by the Sloan Digital Sky Survey (SDSS) Data Release 8 catalog. This includes often…
The temperatures of the heavy ions ($T_i$) in the solar corona provide critical information about the heating mechanism of the million-degree corona. However, the measurement of $T_i$ is usually challenging due to the nonthermal motion,…
Some of local sources of the slow solar wind can be associated with spectroscopically detected plasma outflows at edges of active regions accompanied with specific signatures in the inner corona. The EUV telescopes (e.g. SPIRIT/CORONAS-F,…
The EUI instrument on the Solar Orbiter spacecraft has obtained the most stable, high-resolution images of the solar corona from its orbit with a perihelion near 0.4 AU. A sequence of 360 images obtained at 17.1 nm, between 25-Oct-2022…