Sequential Coronal Mass Ejections from AR8038 in May 1997
| Autor: | Yan Li, B. J. Lynch, George H. Fisher, Yang Liu, Janet G. Luhmann, Guillermo Stenborg, Brian T. Welsch, R. W. Nightingale |
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| Jazyk: | angličtina |
| Rok vydání: | 2010 |
| Předmět: |
Sigmoid
Astrophysics 01 natural sciences law.invention Meteorology/Climatology law EUV dimming 0103 physical sciences Coronal mass ejection 010303 astronomy & astrophysics Physics Extraterrestrial Physics Space Sciences Magnetic energy 010308 nuclear & particles physics Astronomy and Astrophysics Corona Magnetic flux Magnetic field Flow velocity Space and Planetary Science Poynting vector Astrophysics and Astroparticles Flare |
| Zdroj: | Li, Y.; Lynch, B. J.; Welsch, B. T.; Stenborg, G. A.; Luhmann, J. G.; Fisher, G. H.; et al.(2010). Sequential Coronal Mass Ejections from AR8038 in May 1997. Solar Physics: A Journal for Solar and Solar-Stellar Research and the Study of Solar Terrestrial Physics, 264(1), pp 149-164. doi: 10.1007/s11207-010-9547-y. Retrieved from: http://www.escholarship.org/uc/item/8d01c0tw |
| DOI: | 10.1007/s11207-010-9547-y. |
| Popis: | Three homologous coronal mass ejections (CMEs) occurred on 5, 12 and 16 May 1997 from the single magnetic polarity inversion line (PIL) of AR8038. The three events together provide STEREO-like quadrature views of the 12 May 1997 CME and EIT double dimming. The recurrent CMEs with the nearly identical post-CME potential state and the ‘sigmoid to arcade to sigmoid’ transformations indicate a repeatable store – release – restore process of the free energy. How was the free magnetic energy re-introduced to the potential state corona after each release in this decaying active region? Making use of the known time interval bounded by the adjacent homologous CMEs, we made the following measures. The unsigned magnetic flux of AR8038, ΦAR, decreased by approximately 18% during 66 h, while the unsigned flux, ΦPIL, in a Gaussian-weighted PIL-region containing the flare site increased by about 50% during 36 hrs prior to the C1.3 flare on 12 May 1997. The significant increase of ΦPIL demonstrates the magnetic gradient increase and the build-up of free energy in the PIL-region during the time leading to the eruption. Fourier local correlation tracking (FLCT) flow speed in AR8038 ranges from 0 to 292.8 m s−1 with a mean value of 63.2 m s−1. The flow field contains a persistent converging flow towards the flaring PIL and an effective shear flow distributed in the AR. Minor angular motions were found. An integrated proxy Poynting flux S h estimates the energy input to the corona to be on the order of 1.15×1032 erg during the 66 hrs before the C1.3 flare. It suggests that sufficient energy for a flare/CME can be introduced to the corona on the order of several days by the flows deduced from photospheric magnetic field motions in this small decaying active region. |
| Databáze: | OpenAIRE |
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