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Kohl, J. L.; Noci, G.; Antonucci, E.; Tondello, G.; Huber, M. C. E.; Gardner, L. D.; Nicolosi, P.; Strachan, L.; Fineschi, Silvano; Raymond, J. C.; Romoli, M.; Spadaro, D.; Panasyuk, A. V.; Siegmund, O. H. W.; Benna, C.; Ciaravella, A.; Cranmer, Steven R.; Giordano, S.; Karovska, M.; Martin, R.; Michels, J.; Modigliani, A.; Naletto, G.; Pernechele, Claudio; Poletto, G.; Smith, P. L.

doi:10.1023/a:1004903206467

Cited by 356 publications

(221 citation statements)

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“…The UVCS Data Analysis and processing Software (DAS, originally developed by C. Benna, A. van Ballegoijen, J. Raymond and S. Giordano) was used for flat-field correction, wavelength and radiometric calibration, removal of image distortion, and spectra extraction (Gardner et al 1996;Kohl et al 1997). Panasyuk's package (available from the Harvard-Smithsonian Center for Astrophysics website: cfa-www.harvard.edu/uvcs) was used to remove the stray light contribution to both the H i Lyα and O vi doublet lines, as well as the contribution from the interplanetary scattered Lyα line contained in the observed Lyα profile.…”

Section: Observations and Data Analysismentioning

confidence: 99%

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Physical parameters of a mid-latitude streamer during the declining phase of the solar cycle

Spadaro

Susino

Ventura

et al. 2007

A&A

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Context. Investigating the physical properties of solar coronal streamers is important for understanding their role in the global magnetic structure of the extended solar atmosphere, as well as in the generation of the slow solar wind. Aims. We hope to contribute as completely as possible to the ongoing SOHO instruments campaign devoted to the study of the physical characteristics of coronal streamers at various heliocentric distances. Results. Electron densities and temperatures, H i and O vi kinetic temperatures, and outflow velocities were derived from the line intensities and widths, as well as from the O vi line intensity ratio in the 1.6−5 R range of heights, limited to the central region of the streamer. To our knowledge, the H i outflow velocities obtained in this work are the first ones determined inside a streamer structure. They are significantly lower than those of the O vi ions. This, together with the O vi kinetic temperatures that are much higher than the H i ones, suggest that the absorption of Alfvén waves at the ion cyclotron frequency might also occur inside streamers. Methods. We analyzed ultraviolet H iConclusions. In comparison with other streamers described in the literature, the structure examined in this work generally exhibits lower electron density and neutral hydrogen kinetic temperature. Conversely, the O vi kinetic temperature and outflow velocity radial profiles are consistent with the results for the other examined streamers.

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Section: Observations and Data Analysismentioning

confidence: 99%

“…2 and, also, cf. Kohl et al 1997). The spectral characteristics of the emission lines synthesized by this initial model are compared with the measured spectroscopic observables.…”

Section: Diagnostics Of Physical Parametersmentioning

confidence: 99%

Physical parameters of a mid-latitude streamer during the declining phase of the solar cycle

Spadaro

Susino

Ventura

et al. 2007

A&A

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“…temperature anisotropy: 10 < T ⊥ /T < 100 (see Kohl et al 1997;Li et al 1998;Cranmer et al 1999a,b,c and others). In addition, the heavy ions are deduced to be hotter and faster than the protons.…”

Section: Introductionmentioning

confidence: 95%

“…Information on the densities, the temperatures, the bulk velocities and the velocity distributions of different species can be obtained from the total intensity, Doppler width and shift of multiple line profiles with the appropriate instrument, such as the UltraViolet Coronagraph Spectrometer (UVCS; Kohl et al 1995Kohl et al , 1997 onboard the Solar and Heliospheric Observatory (SoHO; Domingo et al 1995).…”

Section: Introductionmentioning

confidence: 99%

Effect of the electron density stratification on off-limb O VI line profiles: How large is the velocity distribution anisotropy in the solar corona?

Raouafi

Solanki

2004

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Abstract. Coronagraphic spectral observations carried out with UVCS on SoHO have shown that the velocity distribution in the solar corona is highly anisotropic. Here we examine the influence of the density stratification on the interpretation of such observations. In particular, we investigate the profiles of O  lines emitted in the corona by employing an analytical 2-D model of the large scale coronal magnetic field and solar wind. We concentrate on the polar coronal holes and take into account the integration along the line of sight. We find that at distances greater than 1 R from the solar surface the widths of the emitted lines are significantly affected by the details of the adopted electron density profiles. In particular, the densities deduced by Doyle et al. (1999a,b) from SoHO data result in O  profiles whose widths and intensity ratio are relatively close to the values observed by UVCS/SoHO although only isotropic velocity distributions are employed. Hence we expect that the magnitude of anisotropy of the velocity distribution deduced from UVCS data depends strongly on the adopted density profile.

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“…The O vi D 2 line is one of the strongest spectral lines emitted by the solar corona until high altitudes (Vial et al 1980;Kohl et al 1998;Xing Li et al 1998; and other papers related to UVCS (Ultraviolet Coronagraph Spectrometer: Kohl et al 1995Kohl et al , 1997 on SoHO. The O vi D 2 line (and also the O vi λ1037.61 line, hereafter D 1 line) is formed in the chromosphere-corona transition region.…”

Section: Introductionmentioning

confidence: 99%

Linear polarization of the $\ion{O}{iv}$λ1031.92 coronal line

Raouafi

Sahal‐Bréchot

Lemaire

2002

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Abstract. Numerical computation results of the linear polarization parameters of the O vi λ1031.92 coronal line are presented. They are based on theoretical results obtained by Raouafi (2002 and2000), which give the Stokes parameters of a resonance scattering spectral line sensitive simultaneously to the Hanle effect and to the Doppler redistribution. In the present coronal case, the Hanle effect is due to the coronal magnetic field and the Doppler redistribution to the macroscopic motion of the scattering O 5+ coronal ions (solar wind velocity field vector). Constraints on the coronal magnetic field vector and on the solar wind velocity field vector are obtained by comparing the numerical results and the linear polarization measurements of the O vi λ1031.92 coronal line obtained through particular observations performed by SUMER/SoHO.

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Cited by 356 publications

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Physical parameters of a mid-latitude streamer during the declining phase of the solar cycle

Physical parameters of a mid-latitude streamer during the declining phase of the solar cycle

Effect of the electron density stratification on off-limb O VI line profiles: How large is the velocity distribution anisotropy in the solar corona?

Linear polarization of the $\ion{O}{iv}$λ1031.92 coronal line

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