The correlation between coronal Doppler shifts 
 and the supergranular network

Aiouaz, T.; Peter, Hardi; Lemaire, Philippe

doi:10.1051/0004-6361:20042159

Cited by 30 publications

(52 citation statements)

References 29 publications

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“…Concentrated outflow of Ne 7+ ions could be identified along coronal-hole network lanes and, in particular, near their intersections ). However, Aiouaz et al (2005a) located the maximum outflow near the network boundaries 7 , and Popescu et al (2004) identified outflow regions there in the relatively cool O III 70.3 nm line. Above the chromospheric network, the outflow appears to be strongest in the dark regions of the coronal holes and not in the bright polar plumes Patsourakos and Vial 2000).…”

Section: Coronal Holes Polar Plumes and The Fast Solar Windmentioning

confidence: 98%

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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Section: Coronal Holes Polar Plumes and The Fast Solar Windmentioning

confidence: 98%

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

et al. 2007

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“…It is believed that part of the magnetic network flux opens into the corona in the shape of funnels, whilst the rest of the network consists of a dense population of lowlying loops with lengths less than 10 4 km and varying orientations (Dowdy et al 1986;Marsch & Tu 1997;Peter 2001). Magnetic loops reaching to the height of the chromosphere and TR can be swept by the supergranular flow from the cell interior to its boundaries, where they can interact with magnetic funnels, and by reconnection may supply mass and energy to the funnels (Axford et al 1999;Aiouaz et al 2005;Aiouaz 2008;He et al 2007;McIntosh et al 2007;Tian et al 2008aTian et al , 2009). Reconnection at the interface between cool side loops and the network flux tubes may occur in the chromosphere and TR, resulting in the solar wind outflow (Tu et al 2005;He et al 2008;Büchner & Nikutowski 2005;Tian et al 2008bTian et al , 2010 or upflows along loop legs (Tian et al 2008a(Tian et al , 2009, and downflows at lower layers.…”

Section: Magneto-convection In the Chromospherementioning

confidence: 99%

Horizontal supergranule-scale motions inferred from TRACE ultraviolet observations of the chromosphere

Potts

Marsch

Attié

et al. 2010

A&A

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Aims. We study horizontal supergranule-scale motions revealed by TRACE observation of the chromospheric emission, and investigate the coupling between the chromosphere and the underlying photosphere. Methods. A highly efficient feature-tracking technique called balltracking has been applied for the first time to the image sequences obtained by TRACE (transition region and coronal explorer) in the passband of white light and the three ultraviolet passbands centered at 1700 Å, 1600 Å, and 1550 Å. The resulting velocity fields have been spatially smoothed and temporally averaged in order to reveal horizontal supergranule-scale motions that may exist at the emission heights of these passbands. Results. We find indeed a high correlation between the horizontal velocities derived in the white-light and ultraviolet passbands. The horizontal velocities derived from the chromospheric and photospheric emission are comparable in magnitude. Conclusions. The horizontal motions derived in the UV passbands might indicate the existence of a supergranule-scale magnetoconvection in the chromosphere, which may shed new light on the study of mass and energy supply to the corona and solar wind at the height of the chromosphere. However, it is also possible that the apparent motions reflect the chromospheric brightness evolution as produced by acoustic shocks which might be modulated by the photospheric granular motions in their excitation process, or advected partly by the supergranule-scale flow towards the network while propagating upward from the photosphere. To reach a firm conclusion, it is necessary to investigate the role of granular motions in the excitation of shocks through numerical modeling, and future high-cadence chromospheric magnetograms must be scrutinized.

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“…They can be observed in space-based X-ray (Wilcox, 1968;Altschuler, Trotter, and Orrall, 1972;Hundhausen, 1972) and EUV images (Newkirk, 1967;Tousey, Sandlin, and Purcell, 1968;Del Zanna and Bromage, 1999). More recent studies on the outflow dynamics and Doppler shifts of coronal holes improved the understanding of CHs being the source of the fast solar wind (Hassler et al, 1999;Peter and Judge, 1999;Xia, Marsch, and Curdt, 2003;Aiouaz, Peter, and Lemaire, 2005).…”

Section: Introductionmentioning

confidence: 99%

Real-Time Solar Wind Prediction Based on SDO/AIA Coronal Hole Data

et al. 2015

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We present an empirical model based on the visible area covered by coronal holes close to the central meridian in order to predict the solar wind speed at 1 AU with a lead time up to four days in advance with a 1-h time resolution. Linear prediction functions are used to relate coronal hole areas to solar wind speed. The function parameters are automatically adapted by using the information from the previous 3 Carrington Rotations. Thus the algorithm automatically reacts on the changes of the solar wind speed during different phases of the solar cycle. The adaptive algorithm has been applied to and tested on SDO/AIA-193Å observations and ACE measurements during the years 2011 − 2013, covering 41 Carrington Rotations. The solar wind speed arrival time is delayed and needs on average 4.02 ± 0.5 days to reach Earth. The algorithm produces good predictions for the 156 solar wind high speed streams peak amplitudes with correlation coefficients of cc ≈ 0.60. For 80% of the peaks, the predicted arrival matches within a time window of 0.5 days of the ACE in situ measurements. The same algorithm, using linear predictions, was also applied to predict the magnetic field strength from coronal hole areas but did not give reliable predictions (cc ≈ 0.2).

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The correlation between coronal Doppler shifts and the supergranular network

Cited by 30 publications

References 29 publications

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

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

Horizontal supergranule-scale motions inferred from TRACE ultraviolet observations of the chromosphere

Real-Time Solar Wind Prediction Based on SDO/AIA Coronal Hole Data

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