Artículo
Abstract:
The dynamic flare of 6 November, 1980 (max ≈ 15:26 UT) developed a rich system of growing loops which could be followed in Hα for 1.5 hr. Throughout the flare, these loops, near the limb, were seen in emission against the disk. Theoretical computations of deviations from LTE populations for a hydrogen atom reveal that this requires electron densities in the loops close to, or in excess of 1012 cm -3. From measured widths of higher Balmer lines the density at the tops of the loops was found to be 4 x 1012 cm -3 if no non-thermal motions were present, or 5 × 1011 cm -3 for a turbulent velocity of ~ 12 km s -1. It is now general knowledge that flare loops are initially observed in X-rays and become visible in Hα only after cooling. For such a high density, a loop would cool through radiation from 107 to 104 K within a few minutes so that the dense Hα loops should have heights very close to the heights of the X-ray loops. This, however, contradicts the observations obtained by the HXIS and FCS instruments on board SMM which show the X-ray loops at much higher altitudes than the loops in Hα. Therefore, we suggest that the density must have been significantly lower when the loops were formed and that the flare loops were apparently both shrinking and increasing in density while cooling. © 1987 D. Reidel Publishing Company.
Registro:
| Documento: | Artículo |
| Título: | Multi-thermal observations of newly formed loops in a dynamic flare |
| Autor: | Švestka, Z.F.; Fontenla, J.M.; Machado, M.E.; Martin, S.F.; Neidig, D.F.; Poletto, G. |
| Filiación: | Laboratory for Space Research Utrecht, SRON, Netherlands IAFE, Buenos Aires, Argentina NAS/NRC Research Associate, Space Science Laboratory, NASA MSFC, United States Space Science Laboratory, NASA MSFC, Huntsville, 35812, AL, United States Solar Astronomy, CALTECH, Passadena, 91125, CA, United States Air Force Geophysics Laboratory, National Solar Observatory, Sacramento Peak, Sunspot, 88349, NM, United States Osservatorio Astrofisico di Arcetri, Firenze, Italy |
| Año: | 1987 |
| Volumen: | 108 |
| Número: | 2 |
| Página de inicio: | 237 |
| Página de fin: | 250 |
| DOI: | http://dx.doi.org/10.1007/BF00214164 |
| Título revista: | Solar Physics |
| Título revista abreviado: | Sol Phys |
| ISSN: | 00380938 |
| Registro: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00380938_v108_n2_p237_Svestka |
Referencias:
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Citas:
---------- APA ----------
Švestka, Z.F., Fontenla, J.M., Machado, M.E., Martin, S.F., Neidig, D.F. & Poletto, G. (1987) . Multi-thermal observations of newly formed loops in a dynamic flare. Solar Physics, 108(2), 237-250.http://dx.doi.org/10.1007/BF00214164
---------- CHICAGO ----------
Švestka, Z.F., Fontenla, J.M., Machado, M.E., Martin, S.F., Neidig, D.F., Poletto, G. "Multi-thermal observations of newly formed loops in a dynamic flare" . Solar Physics 108, no. 2 (1987) : 237-250.http://dx.doi.org/10.1007/BF00214164
---------- MLA ----------
Švestka, Z.F., Fontenla, J.M., Machado, M.E., Martin, S.F., Neidig, D.F., Poletto, G. "Multi-thermal observations of newly formed loops in a dynamic flare" . Solar Physics, vol. 108, no. 2, 1987, pp. 237-250.http://dx.doi.org/10.1007/BF00214164
---------- VANCOUVER ----------
Švestka, Z.F., Fontenla, J.M., Machado, M.E., Martin, S.F., Neidig, D.F., Poletto, G. Multi-thermal observations of newly formed loops in a dynamic flare. Sol Phys. 1987;108(2):237-250.http://dx.doi.org/10.1007/BF00214164
