[en] In this work, we report on a cold, bright portion of an active region observed by the Hinode/EUV Imaging Spectrometer. The emitting plasma was very bright at transition region temperatures, and the intensities of lines of ions formed between 10⁵ and 10⁶ K were enhanced over normal values. The data set constitutes an excellent laboratory where the emission of transition region ions can be tested. We first determine the thermal structure of the observed plasma, and then we use it (1) to develop a spectral atlas, and (2) to assess the quality of CHIANTI atomic data by comparing predicted emissivities with observed intensities. We identify several lines never observed before in solar spectra, and find an overall very good agreement between CHIANTI-predicted emissivities and observations.

[en] In this work, we study Fe VIII lines emitted in the 1000-1200 A wavelength range that originate from levels that also emit transitions observed in the 190-200 A wavelength range. The intensity ratios between such lines depend on atomic physics parameters only and not on the physical parameters of the emitting plasma: they are excellent tools to verify the relative intensity calibration of instruments operating in those wavelength ranges. We first carry out extensive atomic physics calculations to improve the accuracy of the predicted intensity ratios of those lines. We then compare the results with simultaneous Hinode/Extreme Ultraviolet Imaging Spectrometer and SOHO/SUMER observations of an off-disk quiet-Sun region, identify four new lines in the 1000-1200 A range, and discuss their use for instrument calibration purposes.

[en] In this work, we study joint observations of Hinode/EUV Imaging Spectrometer (EIS) and Solar and Heliospheric Observatory/Solar Ultraviolet Measurement of Emitted Radiation of Fe IX lines emitted by the same level of the high energy configuration 3s ²3p ⁵4p. The intensity ratios of these lines are dependent on atomic physics parameters only and not on the physical parameters of the emitting plasma, so that they are excellent tools to verify the relative intensity calibration of high-resolution spectrometers that work in the 170-200 A and 700-850 A wavelength ranges. We carry out extensive atomic physics calculations to improve the accuracy of the predicted intensity ratio, and compare the results with simultaneous EIS-SUMER observations of an off-disk quiet Sun region. We were able to identify two ultraviolet lines in the SUMER spectrum that are emitted by the same level that emits one bright line in the EIS wavelength range. Comparison between predicted and measured intensity ratios, wavelengths and energy separation of Fe IX levels confirms the identifications we make. Blending and calibration uncertainties are discussed. The results of this work are important for cross-calibrating EIS and SUMER, as well as future instrumentation.

[en] In this work, we have used simultaneous observations of the quiet Sun above the solar west limb obtained with the Hinode/Extreme ultraviolet Imaging Spectrograph and SOHO/SUMER instruments to determine their relative intensity calibration. We used two different methods: intensity ratios of lines emitted by the same upper level and observed in the spectral ranges of the two spectrometers, and the determination of the differential emission measure and total emission measure of the plasma. We review the uncertainties in our analysis and conclude that the relative calibration of the two instruments, as it can be determined from the standard data reduction software of each of them, is correct within uncertainties.

[en] We have used the Extreme Ultraviolet Imaging Spectrometer on the Hinode spacecraft to observe large areas of outflow near an active region. These outflows are seen to persist for at least 6 days. The emission line profiles suggest that the outflow region is composed of multiple outflowing components, Doppler-shifted with respect to each other. We have modeled this scenario by imposing a double-Gaussian fit to the line profiles. These fits represent the profile markedly better than a single-Gaussian fit for Fe XII and XIII emission lines. For the fastest outflowing components, we find velocities as high as 200 km s^-1. However, there remains a correlation between the fitted line velocities and widths, suggesting that the outflows are not fully resolved by the double-Gaussian fit and that the outflow may be comprised of further components.

[en] Nineteen recombination lines of O VI are identified in ultraviolet and visible spectra of the symbiotic nova RR Telescopii at wavelengths between 1122 and 6203 Å. Only three of the lines have previously been reported from astronomical spectra, and eight lines have never been reported from either astronomical or laboratory spectra. The lines represent transitions between levels with principal quantum numbers up to 13, and the strongest lines by flux occur at 1124.82, 2070.90, and 3434.66 Å, corresponding to transitions 4-5, 5-6, and 6-7. As the lines are produced by recombination onto O VII, they potentially allow O VII emitting regions in astrophysical plasmas to be probed at ultraviolet and visible wavelengths that otherwise can only be studied at X-ray wavelengths.

[en] A detailed study of emission lines from Fe VII, Fe VIII, and Fe IX observed by the EUV Imaging Spectrometer on board the Hinode satellite is presented. Spectra in the ranges 170-212 A and 246-292 A show strongly enhanced lines from the upper solar transition region (temperatures 5.4 ≤ log T ≤ 5.9) allowing a number of new line identifications to be made. Comparisons of Fe VII lines with predictions from a new atomic model reveal new plasma diagnostics, however there are a number of disagreements between theory and observation for emission line ratios insensitive to density and temperature, suggesting improved atomic data are required. Line ratios for Fe VIII also show discrepancies with theory, with the strong λ185.21 and λ186.60 lines underestimated by 60%-80% compared to lines between 192 and 198 A. A newly identified multiplet between 253.9 and 255.8 A offers excellent temperature diagnostic opportunities relative to the lines between 185 and 198 A, however the atomic model underestimates the strength of these lines by factors of 3-6. Two new line identifications are made for Fe IX at wavelengths 176.959 A and 177.594 A, while seven other lines between 186 and 200 A are suggested to be due to Fe IX but for which transition identifications cannot be made. The new atomic data for Fe VII and Fe IX are demonstrated to significantly modify models for the response function of the Transition Region And Coronal Explorer 195 A imaging channel, affecting temperature determinations from this channel. The data will also affect the response functions for other solar EUV imaging instruments such as SOHO/EIT, STEREO/EUVI, and the upcoming AIA instrument on the Solar Dynamics Observatory.

[en] The signatures of energy release and energy transport for a kink-unstable coronal flux rope are investigated via forward modeling. Synthetic intensity and Doppler maps are generated from a 3D numerical simulation. The CHIANTI database is used to compute intensities for three Hinode /EIS emission lines that cover the thermal range of the loop. The intensities and Doppler velocities at simulation-resolution are spatially degraded to the Hinode /EIS pixel size (1″), convolved using a Gaussian point-spread function (3″), and exposed for a characteristic time of 50 s. The synthetic images generated for rasters (moving slit) and sit-and-stare (stationary slit) are analyzed to find the signatures of the twisted flux and the associated instability. We find that there are several qualities of a kink-unstable coronal flux rope that can be detected observationally using Hinode /EIS, namely the growth of the loop radius, the increase in intensity toward the radial edge of the loop, and the Doppler velocity following an internal twisted magnetic field line. However, EIS cannot resolve the small, transient features present in the simulation, such as sites of small-scale reconnection (e.g., nanoflares).

[en] We discuss observations of chromospheric evaporation for a complex flare that occurred on 2012 March 9 near 03:30 UT obtained from the Extreme-ultraviolet Imaging Spectrometer (EIS) on board the Hinode spacecraft. This was a multiple event with a strong energy input that reached the M1.8 class when observed by EIS. EIS was in raster mode and fortunately the slit was almost at the exact location of a significant energy input. Also, EIS obtained a full-CCD spectrum of the flare, i.e., the entire CCD was readout so that data were obtained for about the 500 lines identified in the EIS wavelength ranges. Chromospheric evaporation characterized by 150-200 km s^–1 upflows was observed in multiple locations in multi-million degree spectral lines of flare ions such as Fe XXII, Fe XXIII, and Fe XXIV, with simultaneous 20-60 km s^–1 upflows in million degree coronal lines from ions such as Fe XII-Fe XVI. The behavior of cooler, transition region ions such as O VI, Fe VIII, He II, and Fe X is more complex, but upflows were also observed in Fe VIII and Fe X lines. At a point close to strong energy input in space and time, the flare ions Fe XXII, Fe XXIII, and Fe XXIV reveal an isothermal source with a temperature close to 14 MK and no strong blueshifted components. At this location there is a strong downflow in cooler active region lines from ions such as Fe XIII and Fe XIV, on the order of 200 km s^–1. We speculate that this downflow may be evidence of the downward shock produced by reconnection in the current sheet seen in MHD simulations. A sunquake also occurred near this location. Electron densities were obtained from density sensitive lines ratios from Fe XIII and Fe XIV. Atmospheric Imaging Assembly (AIA) observations from the Solar Dynamics Observatory are used with JHelioviewer to obtain a qualitative overview of the flare. However, AIA data are not presented in this paper. In summary, spectroscopic data from EIS are presented that can be used for predictive tests of models of chromospheric evaporation as envisaged in the Standard Flare Model.

[en] The development of a slotted substrate integrated waveguide antenna with an epsilon near zero (ENZ) material is presented. Here, an ENZ waveguide structure is used in the design. The ENZ material is used to realize unconventional tunneling of electromagnetic energy with ultra-thin subwavelength channels and it is considered to attain a highly directive narrow band antenna. The effect of the various parameters of the antenna is studied by simulation. A prototype is fabricated and the measurement results are compared with the simulated values. (paper)