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Issue A&A
Volume 473, Number 3, October III 2007
Page(s) 951 - 957
Section The Sun
DOI http://dx.doi.org/10.1051/0004-6361:20077255



A&A 473, 951-957 (2007)
DOI: 10.1051/0004-6361:20077255

On the relationship between coronal waves associated with a CME on 5 March 2000

D. Tripathi1 and N.-E. Raouafi2

1  Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Wilberforce Road, Cambridge, CB3 0WA, UK
    e-mail: D.Tripathi@damtp.cam.ac.uk
2  National Solar Observatory, 950 North Cherry Avenue, Tucson, AZ 85719, USA
    e-mail: nraouafi@nso.edu

(Received 7 February 2007 / Accepted 25 July 2007 )

Abstract
Aims.To study the relationship between coronal mass ejection (CME) associated waves.
Methods.Analysis of CME eruption observations on 5 Mar. 2000 recorded by the Large Angle Spectrometric Coronagraph (LASCO), the Ultraviolet Coronagraph Spectrometer (UVCS), and the Extreme-ultraviolet Imaging Telescope (EIT) on board the Solar and Heliospheric Observatory (SOHO).
Results.Images recorded by the LASCO/C2 show a clear deflection and kink in a streamer located eastward of the CME. The kink in the streamer propagated outwards along with the associated CME. No CME material was seen between the bright front of the CME and the streamer. UVCS spectra show large spectral line broadening, Doppler shifts and intensity changes in the $\ion{O}{vi}$ ($\lambda$1032 & 1037) lines. Moreover, intensity enhancements in lines such as $\ion{Si}{xii}$ $\lambda$ 520 and $\ion{Mg}{x}$ $\lambda$ 625 forming at very high temperatures (>2 MK; not often observed in the corona) were also observed. EIT images show the propagation of a wave from the CME source region. The speed of the wave was about 55 km s-1 and it propagated predominantly in the North-East direction from the source region. Furthermore, it does not propagate through active regions and coronal holes. The deflection in the streamer recorded in the LASCO/C2 was in the same direction as that of the EIT wave.
Conclusions.Spatial and temporal correlations show that the deflection and the propagation of the kink in the streamer (based on the LASCO data), and plasma heating and spectral line broadening (based on the UVCS data), are basically due to a CME-driven shock wave. The spatial and temporal correlations between the EIT wave and the shock wave provide strong evidence in favor of the interpretation that the EIT waves are indeed the counterpart of CME-driven shock waves in the lower corona. Although, we cannot rule out the possibility that the EIT waves are just a manifestation of the stretching of the field lines due to the outward propagation of the CMEs.


Key words: Sun: activity -- Sun: corona -- Sun: coronal mass ejections (CMEs) -- Sun: UV radiation -- Sun: chromosphere -- Sun: filaments



© ESO 2007


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