The solar disk spectrum between 660 and 1175 Å (first order)
obtained by SUMER on SOHO

Curdt, W.; Feldman, U.; Laming, J. M.; Wilhelm, K.; Schühle, U.; Lemaire, Philippe

doi:10.1051/aas:1997265

Cited by 67 publications

(39 citation statements)

References 32 publications

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“…Line Curdt et al (1997); c Arnaud & Rothenflug (1985); d Ridgeley & Burton (1972); e Edlén (1983); f Dammasch et al (1999); g Denne & Hinnov (1984); h Edlén (1984); i Edlén (1985); j Kaufman & Martin (1993).…”

Section: Wavelengthmentioning

confidence: 99%

The inner solar corona seen by SUMER, LASCO/C1, and EIT: Electron densities and temperatures during the rise of the new solar cycle

Wilhelm

Inhester

Newmark

2002

A&A

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Abstract. Detailed investigations of the corona and the source regions of the solar wind have become possible with spectroscopic and imaging instruments on the Solar and Heliospheric Observatory (SOHO). We present observations in the extreme ultraviolet (EUV), pertinent to the generation of the slow solar wind, which were obtained by the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) spectrograph and by the Extreme-ultraviolet Imaging Telescope (EIT) in early 1998 under relatively quiet solar conditions, but with several active regions of the new solar cycle present. At the same time, forbidden iron lines in the visible were observed by the Large-Angle Spectroscopic Coronagraph (LASCO/C1). We study, in particular, the plasma parameters and the spatial structures of the low-altitude streamer regions, and find an electron density of ne ≈ 2 × 10 8 cm −3 at 5 Mm above the equatorial limb for the coronal plasma, and ne = (2 to 6) × 10 9 cm −3 for the plasma at transition-region temperatures. High-temperature regions have been found at mid-latitudes with electron temperatures of Te ≈ 1.4 × 10 6 K at heights of about 80 Mm and lower temperatures near the equator.

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Section: Wavelengthmentioning

confidence: 99%

The inner solar corona seen by SUMER, LASCO/C1, and EIT: Electron densities and temperatures during the rise of the new solar cycle

Wilhelm

Inhester

Newmark

2002

A&A

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“…Unfortunately, the lines belonging to the registered wavelength range are not free of contribution from other emission lines, mainly He ii (T = 5.0 × 10 4 K) and/or O i (T = 1.5 × 10 4 K) lines. Table 1 gives the blends as identified by Curdt et al (1997Curdt et al ( , 2001) and Warren et al (1998). The Ly 8 line is excluded from our analysis because it is blended by N iv lines which have a strong contribution in the very bright network and especially during explosive events.…”

Section: Line Blendsmentioning

confidence: 99%

Temporal evolution of different temperature plasma during explosive events

Madjarska¹,

Doyle²

2002

A&A

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Abstract. High cadence observations (10 s exposure time) obtained with the SUMER spectrometer on-board SoHO in the Ly 6 (20 000 K) and S vi (200 000 K) lines reveal new insight on the nature of explosive events. A time delay in the response of the S vi line with respect to the Ly 6 line has been observed, with the Ly 6 line responding with about 20-40 s earlier. A temporal series obtained with 30 s exposure time and covering the entire Lyman series plus O i, C ii and S vi (temperature range from 15 000 to 200 000 K) has also been explored showing the response of all these lines during transient phenomena. New common features linking explosive events and blinkers were found. During explosive events, the central intensity increases between 1.6 and 2.0 times the pre-event value while the same range of intensity increase was already reported during blinker phenomena. On the other hand the maximum intensity increase in Ly 6 was only 13%.

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“…We have selected five hydrogen Lyman lines: Ly5 (937.8Å), Ly7 (926.2Å), Ly9 (920.9Å), Ly11 (918.1Å) and Ly15 (915.3Å), and a Lyman continuum window around 907Å for the detailed study. For detailed line identifications see Curdt et al (1997), Curdt & Heinzel (1998).…”

Section: Observations and Data Reductionmentioning

confidence: 99%

Temporal and spatial variations of the quiet upper chromosphere from SOHO/SUMER observations of hydrogen Lyman lines

Kariyappa

Varghese

Curdt

2001

A&A

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Abstract.We have analyzed a time series of spectra in the hydrogen Lyman lines and the Lyman continuum obtained by the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) spectrometer on the SOlar Heliospheric Observatory (SOHO). The time series of about 2 hours and 22 min was obtained on 1999 March 9 in a quiet region near the center of the solar disk. For our analysis, we have selected a Lyman continuum window around 907Å, and the five Lyman lines: Ly5 (937.8Å), Ly7 (926.2Å), Ly9 (920.9Å), Ly11 (918.1Å), and Ly15 (915.3Å). We derived the central intensity of these lines for a large number of locations over the network and inter-network regions. We found from their line-center intensity time series and from the power spectrum analysis that the network and inter-network regions at the upper chromosphere are associated with 5-7 min and 3-min period of intensity oscillations, respectively. Phase difference analysis shows that there is a preponderance of upward-propagating waves in the upper chromosphere. The phase velocity was estimated to be roughly 4-5 km s −1 in the network regions. In addition, a Fast Fourier analysis has been performed in the spatial domain, all along the slit length used, for all the spectra and for the total duration of the observations. We have detected significant periodic spatial variations with Fourier transform power peaks around 9-10 arcsec and at 4 arcsec. They correspond to the scale of mesogranulation structure and the width of the supergranular boundary, respectively. This provides evidence for the existence of a meso-scale in the upper chromosphere, of the same size as observed in the photosphere and lower chromosphere by earlier studies. We notice that the size (9-10 arcsec) of the meso-scale structures appears to be the same in all Lyman lines and in the continuum, which are formed at different depths in the chromosphere.

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The solar disk spectrum between 660 and 1175 Å (first order) obtained by SUMER on SOHO

Cited by 67 publications

References 32 publications

The inner solar corona seen by SUMER, LASCO/C1, and EIT: Electron densities and temperatures during the rise of the new solar cycle

The inner solar corona seen by SUMER, LASCO/C1, and EIT: Electron densities and temperatures during the rise of the new solar cycle

Temporal evolution of different temperature plasma during explosive events

Temporal and spatial variations of the quiet upper chromosphere from SOHO/SUMER observations of hydrogen Lyman lines

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