Abstracts submitted by Boris Filippov
On Causal Relationships between Eruptive Prominences and Coronal Mass Ejections
Boris Filippov [1] and Serge Koutchmy [2]
[1]Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation; [2]Institut d'Astrophysique de Paris, CNRS and Univ. P. & M. Curie
Many studies revealed a very close association between eruptive prominences and CMEs, both slow and fast CMEs. Sometimes it is possible to follow the material motion starting from the prominence (filament) activation to the CME in the high corona. Remnants of the prominence are found in the bright core of the CME. However, detailed comparisons of the two phenomena reveal problems in explaining CMEs as a continuation of filament eruptions in the upper corona. For example, the heliolatitudes of the disappeared filaments and subsequent coronal ejections sometimes differ by tens of degrees. We discuss this and some other problems of EP-CME association and try to resolve them in the frame of a magnetic flux rope model. In such a situation, the considerable heliographic separation of the observed manifestations of eruption in its initial and final stages may result from non-radial and non-rectilinear motions of flux ropes in the corona due to their interaction with the large-scale magnetic field. Prominences and filaments are the best tracers of the flux ropes in the corona long before the beginning of the eruption. A twisted flux rope is held by the tension of field lines of photospheric sources until parameters of the system reach critical values and a catastrophe happens. The flux rope height above the photosphere is one of these parameters and it is revealed by the height of the filament. We analysed 70 filaments and found that eruptive prominences were near the so-called limit of stability a few days before their eruptions. We believe that a comparison of the real heights of prominences with the calculated critical heights from magnetograms could be a basis for predicting filament eruptions and following CMEs. |
Analysis and interpretation of a fast limb CME with eruptive prominence, C-flare and EUV dimming
S. Koutchmy[1], V. Slemzin[2], B. Filippov[3], J.-C. Noens[4] and D. Romeuf[5]
[1]Institut d'Astrophysique de Paris, CNRS and UPMC; [2]P.N. Lebedev Physical Institute; [3]IZMIRAN; [4]OMP and Pic du Midi Observatory; [5]C.R.I. Claude Bernard Lyon I University
We selected the fast W-limb CME event of December 2, 2003 to fully analyze its erupting phase, taking into account what is seen on disk and off disk. The corresponding erupting prominence was observed at high cadence well above the limb with the Pic du Midi full H-alpha line-flux imaging coronagraph. EUV images with the SOHO/EIT and with the Coronas/SPIRIT space instruments are also used. The eruption started with a fast bright expanding coronal loop registered slightly after by GOES as a C7.2 flare, followed by a brightening and an acceleration phase of the erupting material. Attention is paid to the details at time of the onset and to variations in the fine structure of the prominence, including a possible increase of turbulence inside with heating at its periphery. Difference imaging made using the EUV channels before and after revealed a large dimming at and above the limb, over a 2 hours interval. The total solar corona radiation flux dropped by ~7% in the 19.5 nm channel and by 4% in the 17.5 nm channel. One hour later the CME was observed by the LASCO C2 and C3 coronagraphs. The typical 3-part structure shows a core shaped similarly to the erupted filament/prominence. The total evaluated mass of the escaping CME (~ 1.5.1016 g from C2 LASCO observations) definitely overpasses the estimated mass of the escaping prominence material, reaching a factor of order of 10. Assumptions made to analyze the H-alpha prominence during the erupting phase, as well as the corresponding EUV darkening of the filament observed several days before, made this evaluation uncertain by a factor of at least 2. We quantitatively discuss the observational data set relevant to the mass budget. Based on an extrapolated from photospheric measurements coronal magnetic field, a possible scenario of the event leading to an instability is also proposed, including the heating processes associated to the small scale dynamics inside and around the filament. |
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