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Lemaire, Philippe; Bocchialini, K.; Aletti, V.; Hassler, D. M.; Wilhelm, K.

doi:10.1023/a:1005164905085

Cited by 18 publications

(14 citation statements)

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“…Observations with higher spectral resolution covering the whole temperature range are required to settle this question. Since SUMER mainly samples the lower temperature range our result is consistent with the findings of Lemaire et al (1999), who found Ne VIII 770.43Å to have the same width in quiet Sun and coronal holes, and Stucki et al (2000a), whose data indicate that Fe XII 1242Å is narrower in holes. Figure 10 displays the difference between the wavelengths observed in the coronal hole region and the ones observed in the small µ quiet Sun region.…”

Section: Comparison Of Line Parameterssupporting

confidence: 91%

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Properties of ultraviolet lines observed with the Coronal Diagnostic Spectrometer (CDS/SOHO) in coronal holes and the quiet Sun

Stucki

Solanki

Pike

et al. 2002

A&A

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Abstract.We present an analysis of 14 ultraviolet emission lines belonging to different atoms and ions observed inside polar coronal holes and in the normal quiet Sun. The observations were made with the Coronal Diagnostic Spectrometer (CDS) onboard the Solar and Heliospheric Observatory (SOHO). This study extends previous investigations made with the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) spectrometer to higher temperatures. We compare line intensities, shifts and widths in coronal holes with the corresponding values obtained in the quiet Sun. While all lines formed at temperatures above 7 × 10 5 K show clearly the presence of the hole in their intensities, differences in line width are more subtle, with cooler lines being broader in coronal holes, while hotter lines tend to be narrower. According to the present data all lines are blueshifted inside the coronal hole compared to the normal quiet Sun. Almost all the lines formed between 80 000 K and 600 000 K (i.e. transition-region lines) show a correlation between blueshifts and brightness within coronal holes. This is in agreement with the conclusion reached by Hassler et al. (1999) that the fast solar wind emanates from the network and supports our previous study (Stucki et al. 2000b). For coronal lines, this trend seems to be reversed.

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Section: Comparison Of Line Parameterssupporting

confidence: 91%

“…According to Lemaire et al (1999) and Stucki et al (2000a), the spectral lines are on average broader inside the coronal hole. This increase in line width, which indicates higher non-thermal velocities inside coronal holes, is not so clearly visible in the current data.…”

Section: Comparison Of Line Parametersmentioning

confidence: 92%

Properties of ultraviolet lines observed with the Coronal Diagnostic Spectrometer (CDS/SOHO) in coronal holes and the quiet Sun

Stucki

Solanki

Pike

et al. 2002

A&A

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“…Peter (2000) reported a similar correlation in the networks. A comparable relation between the intensity and line width was obtained by Lemaire et al (1999) for coronal holes and for quiet Sun. Akiyama et al (2005) also found a line width−intensity spatial correlation for a set of TR spectral lines in quiet Sun.…”

Section: Line Widthsupporting

confidence: 76%

Structure of sunspot light bridges in the chromosphere and transition region

Rezaei

2018

A&A

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Context. Light bridges (LBs) are elongated structures with enhanced intensity embedded in sunspot umbra and pores. Aims. We studied the properties of a sample of 60 LBs observed with the Interface Region Imaging Spectrograph (IRIS). Methods. Using IRIS near-and far-ultraviolet spectra, we measured the line intensity, width, and Doppler shift; followed traces of LBs in the chromosphere and transition region (TR); and compared LB parameters with umbra and quiet Sun.Results. There is a systematic emission enhancement in LBs compared to nearby umbra from the photosphere up to the TR. Light bridges are systematically displaced toward the solar limb at higher layers: the amount of the displacement at one solar radius compares well with the typical height of the chromosphere and TR. The intensity of the LB sample compared to the umbra sample peaks at the middle/upper chromosphere where they are almost permanently bright. Spectral lines emerging from the LBs are broader than the nearby umbra. The systematic redshift of the Si iv line in the LB sample is reduced compared to the quiet Sun sample. We found a significant correlation between the line width of ions arising at temperatures from 3 × 10 4 to 1.5 × 10 5 K as there is also a strong spatial correlation among the line and continuum intensities. In addition, the intensity−line width relation holds for all spectral lines in this study. The correlations indicate that the cool and hot plasma in LBs are coupled. Conclusions. Light bridges comprise multi-temperature and multi-disciplinary structures extending up to the TR. Diverse heating sources supply the energy and momentum to different layers, resulting in distinct dynamics in the photosphere, chromosphere, and TR.

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“…Dammasch et al (1999a) found a positive correlation between the radiance and the width of this line, and a similar correlation for the Si II line. Such a relationship was also observed by Lemaire et al (1999) and Wilhelm (2000a) for several lines in quiet-Sun areas and coronal holes. The centre-to-limb variations of the width of many lines observed by Dammasch et al (1999b) suggest a significant amount of horizonal motions in the transition region.…”

Section: The Thermal Structuresupporting

confidence: 70%

Observations of the Sun at Vacuum-Ultraviolet Wavelengths from Space. Part II: Results and Interpretations

et al. 2007

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In Part I of this review, the concepts of solar vacuum-ultraviolet (VUV) observations were outlined together with a discussion of the space instrumentation used for the investigations. A section on spectroradiometry provided some quantitative results on the solar VUV radiation without considering any details of the solar phenomena leading to the radiation. Here, in Part II, we present solar VUV observations over the last decades and their interpretations in terms of the plasma processes and the parameters of the solar atmosphere, with emphasis on the spatial and thermal structures of the chromosphere, transition region and corona of the quiet Sun. In addition, observations of active regions, solar flares and prominences are included as well as of small-scale events. Special sections are devoted to the elemental composition of the solar atmosphere and theoretical considerations on the heating of the corona and the generation of the solar wind.

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Untitled

Cited by 18 publications

References 0 publications

Properties of ultraviolet lines observed with the Coronal Diagnostic Spectrometer (CDS/SOHO) in coronal holes and the quiet Sun

Properties of ultraviolet lines observed with the Coronal Diagnostic Spectrometer (CDS/SOHO) in coronal holes and the quiet Sun

Structure of sunspot light bridges in the chromosphere and transition region

Observations of the Sun at Vacuum-Ultraviolet Wavelengths from Space. Part II: Results and Interpretations

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