An atlas of solar events: 1996–2005
| Autor: | G. E. Artzner, J. P. Delaboudinière, Frédéric Auchère, M. Bougnet |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
Physics
Atmospheric Science Sunspot Aerospace Engineering Astronomy Astronomy and Astrophysics Coronal loop Corona Nanoflares Geophysics Moreton wave Space and Planetary Science Physics::Space Physics Coronal mass ejection Extreme ultraviolet Imaging Telescope Astrophysics::Solar and Stellar Astrophysics General Earth and Planetary Sciences Solar rotation Astrophysics::Earth and Planetary Astrophysics |
| Zdroj: | Advances in Space Research. 38:390-405 |
| ISSN: | 0273-1177 |
| Popis: | Coronal mass ejections (CMEs) are observed in the plane of the sky in coronographic images. As the solar surface is masked by an occulting disk it is not clear whether halo CMEs are directed towards or away from the Earth. Observations of the solar corona on the solar disk by the extreme ultraviolet imaging telescope (EIT) on board the Solar Heliospheric Observatory SoHO can help to resolve this. Quasi-continuous observations of the solar corona were obtained from April 1997 up to the current date at a 12 min cadence in the coronal line of FeXII, as part of a “CME watch program”. At a slower 6 h cadence an additional synoptic program investigates the chromosphere and the corona at four different wavelengths. Large coronal solar events appear when viewing animations of the CME watch program. Fainter events do appear when viewing running difference animations of the CME watch program. When looking for additional spectral information from raw running differences of the synoptic program it is difficult to disentangle intrinsic solar events from the parasitic effect of the solar rotation. We constructed at www.ias.u-psud.fr/medoc/EIT/movies/ an atlas of more than 40,000 difference images from the synoptic programme, corrected for an average solar rotation, as well as more than 200,000 instantaneous and difference images from the CME watch program. We present case studies of specific events in order to investigate the source of darkenings or dimmings in difference images, due to the removal of emitting material, the presence of obscuring material or large changes in temperature. As the beneficial effect of correcting for the solar rotation vanishes at the solar limb, we do not investigate the case of prominence Doppler dimming. As a by-product of the atlas of solar events we obtain a number of quiet time sequences well suited to precisely measure the differential solar rotation by the apparent displacement of tracers. |
| Databáze: | OpenAIRE |
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