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Antonucci, E.; Dodero, M. A.; Giordano, S.

doi:10.1023/a:1026568912809

Cited by 108 publications

(36 citation statements)

References 23 publications

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“…the electron temperature of 1 MK, it has been found necessary to adopt an increasing ion temperature above 1.5 R8 in order to fit the outer DVCS points, rising to 14 MK at 1.8 R8. This is in general agreement with the earlier analysis of Antonucci et al (2000).…”

Section: Extension To Include Dves Interplume Datasupporting

confidence: 93%

Outflow Velocities in Polar Coronal Holes

Gabriel¹,

Bely‐Dubau

Lemaire

et al. 2004

Symp. - Int. Astron. Union

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Abstract. Observations have been carried out using the oxygen VI multiplet ratio 1032/1038 A from SUMER on SOHO. Analysis based on the Doppler dimming method shows that the outflow velocity in polar plumes is higher than that in the interplume region, contrary to many published suggestions. The addition of uves data for the interplume region, leads to a conclusion that the effective oxygen ion "temperature" in the radial direction has to rise to around 14 MK over the height range 1.5 to 1.8 R8'

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Section: Extension To Include Dves Interplume Datasupporting

confidence: 93%

Outflow Velocities in Polar Coronal Holes

Gabriel¹,

Bely‐Dubau

Lemaire

et al. 2004

Symp. - Int. Astron. Union

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“…Figure 3 shows that our choice of N e is able to reproduce the observed line ratios in interplumes with negligible outflow velocity up to 1.3 R¢ . Above this altitude, the comparison with UVCS data obtained on 21 May 1996 in interplume lanes by [4] shows that the region where the fast solar wind is accelerated lies above 1.2 solar radii, as already suggested by [2].…”

Section: Obssupporting

confidence: 77%

“…Recent analyses of SUMER and UVCS data [see e. g. 1,2,3] have shown that the width of UV lines is larger in interplume than in plume regions, hinting to interplumes as the site where energy is preferentially deposited and, possibly, fast wind emanates. Moreover, the [4] analysis of fast polar wind seems to favor the low density regions as sources of the fast wind streams.…”

Section: Introductionmentioning

confidence: 99%

Oxygen abundance in polar coronal holes

Teriaca¹,

Poletto²,

Falchi³

et al. 2001

AIP Conference Proceedings

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Abstract.Fast solar wind is known to emanate from polar coronal holes. However, only recently attention has been given to the problem of where, within coronal holes, fast wind originates. One way to gain information on whether the fast solar wind originates from plumes or interplume regions could consist in comparing the elemental abundances in these regions with the ones characterizing the fast wind. Here we present a first attempt to determine the oxygen abundance in the interplume regions by using spectra taken at times of minimum in the solar cycle (when it is easier to identify these structures) by the SUMER spectrograph aboard SoHO. To this end, we analyze spectra taken in 1996 in polar regions, at altitudes ranging between 1.05 and 1.3 R¢ , finding a value £ 8¤ 5 for the oxygen abundance in the interplume regions. From the analysis of the O VI 1032 to 1037 line intensity ratio we also find no evidence of outflow velocities below 1.2 solar radii in interplume regions, while there are indications that outflow motions start to be significant above 1.5 solar radii. The method used and the assumptions made are discussed in light of the derived values. Our values are compared with previous determinations in the corona and solar wind.

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“…The middle panel of Fig. 3 compares the results of proton and electron temperature with the observed proton temperature [data with error bars are by Esser et al (1999); open squares are UVCS/SOHO observation by Antonucci, Dodero & Giordano (2000)] and electron temperature [open circles are CDS/SOHO observation by Fludra, Del Zanna & Bromage (1999)] in the polar holes and the observed electron temperature in the mid-latitude streamer [filled diamonds and triangles are CDS,UVCS/SOHO by Parenti et al (2000)]. Please note that the proton temperature is higher than the electron temperature in both models.…”

Section: Structure Of Corona and Solar Windmentioning

confidence: 99%

Coronal heating and acceleration of the high/low-speed solar wind by fast/slow MHD shock trains

Suzuki

2004

Monthly Notices of the Royal Astronomical Society

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We investigate coronal heating and acceleration of the high‐ and low‐speed solar wind in the open field region by dissipation of fast and slow magnetohydrodynamical (MHD) waves through MHD shocks. Linearly polarized Alfvén (fast MHD) waves and acoustic (slow MHD) waves travelling upwardly along with a magnetic field line eventually form fast switch‐on shock trains and hydrodynamical shock trains (N waves) respectively to heat and accelerate the plasma. We determine the one‐dimensional structure of the corona from the bottom of the transition region (TR) out to 1 au under the steady‐state condition by solving evolutionary equations for the shock amplitudes simultaneously with the momentum and proton/electron energy equations. Our model reproduces the overall trend of the high‐speed wind from the polar holes and the low‐speed wind from the mid‐ to low‐latitude streamer except the observed hot corona in the streamer. The heating from the slow waves is effective in the low corona to increase the density there, and plays an important role in the formation of the dense low‐speed wind. On the other hand, the fast waves can carry a sizable energy to the upper level to heat the outer corona and accelerate the high‐speed wind effectively. We also study dependence on field strength, B0, at the bottom of the TR and non‐radial expansion of a flow tube, fmax, to find that large B0/fmax≳ 2 but small B0≃ 2 G are favourable for the high‐speed wind and that small B0/fmax≃ 1 is required for the low‐speed wind.

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Cited by 108 publications

References 23 publications

Outflow Velocities in Polar Coronal Holes

Outflow Velocities in Polar Coronal Holes

Oxygen abundance in polar coronal holes

Coronal heating and acceleration of the high/low-speed solar wind by fast/slow MHD shock trains

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