Magnetic Causes of the Eruption of a Quiescent Filament
- 223 Downloads
During the JOP178 campaign in August 2006, we observed the disappearance of our target, a large quiescent filament located at S25°, after an observation time of three days (24 August to 26 August). Multi-wavelength instruments were operating: THEMIS/MTR (“MulTi-Raies”) vector magnetograph, TRACE (“Transition Region and Coronal Explorer”) at 171 Å and 1600 Å and Hida Domeless Solar telescope. Counter-streaming flows (+/−10 km s−1) in the filament were detected more than 24 hours before its eruption. A slow rise of the global structure started during this time period with a velocity estimated to be of the order of 1 km s−1. During the hour before the eruption (26 August around 09:00 UT) the velocity reached 5 km s−1. The filament eruption is suspected to be responsible for a slow CME observed by LASCO around 21:00 UT on 26 August. No brightening in Hα or in coronal lines, no new emerging polarities in the filament channel, even with the high polarimetry sensitivity of THEMIS, were detected. We measured a relatively large decrease of the photospheric magnetic field strength of the network (from 400 G to 100 G), whose downward magnetic tension provides stability to the underlying stressed filament magnetic fields. According to some MHD models based on turbulent photospheric diffusion, this gentle decrease of magnetic strength (the tension) could act as the destabilizing mechanism which first leads to the slow filament rise and its fast eruption.
KeywordsSun: filament, eruption Magnetic field
Unable to display preview. Download preview PDF.
- Démoulin, P.: 2007, Adv. Space Res. 39, 11. 1674. Google Scholar
- Dudik, J., Aulanier, G., Schmieder, B., Bommier, V.: 2007, Solar Phys., submitted. Google Scholar
- Kuin, N., Paul, M., Martens, P.: 1986, In: Poland, A. (ed.) CPP Workshop Proceedings, NASA 2442, 241. Google Scholar
- Moore, R.L., Roumeliotis, G.: 1992, In: Svestka, Z., Jackson, B.V., Machado, M.E. (eds.) IAU 133, Springer, New York. Google Scholar
- Mouradian, Z., Martres, M.J., Soru-Escaut, I.: 1986, In: Poland, A. (ed.) CPP Workshop Proceedings, NASA 2442, 221. Google Scholar
- Schmieder, B., van Driel-Gesztelyi, L.: 2005, In: Dere, K., Wang, J., Yan, Y. (eds.) Coronal and Stellar Mass Ejections, IAU Symp. 226, Cambridge Univ. Press, Cambridge, 149. Google Scholar
- Švetska, Z.: 1986, The Lower Atmosphere of Solar Flares, NSO/Sac Peak Pub., 332. Google Scholar
- Wang, J.X.: 2002, In: Hénoux, J.C., Fang, C., Vilmer, N. (eds) Second French – Chinese Meeting, World Publishing, 145. Google Scholar