Меню
Главная
Случайная статья
Настройки
|
Бомбы Эллермана
Бомбы Эллермана — небольшие короткоживущие яркие точки («микровспышки») в солнечной хромосфере, наблюдаемые в крыльях линии H вблизи солнечных пятен. Существуют, как правило, около 20 минут.
Впервые были отмечены в середине 1910-х годов году астрономом Ф. Эллерманом (англ. Ferdinand Ellerman),[1] в честь которого и были названы.
Типичная энергия, выделяемая в бомбах Эллермана, оценивается в 1027-1028 эрг.
Micro solar flares named after Ferdinand Ellerman[2] who studied this particular Solar Blasts in the early 20th century. They appear as randomly moving filaments as two oppositely charged ions flow meets in the sun photosphere.
We investigate the statistical properties of Ellerman bombs in the dynamic emerging flux region NOAA Active Region 8844, underneath an expanding arch filament system. High-resolution chromospheric H filtergrams (spatial resolution 08), as well as photospheric vector magnetograms (spatial resolution 05) and Dopplergrams, have been acquired by the balloon-borne Flare Genesis Experiment. H observations reveal the first «seeing-free» data set on Ellerman bombs and one of the largest samples of these events. We find that Ellerman bombs occur and recur in preferential locations in the low chromosphere, either above or in the absence of photospheric neutral magnetic lines. Ellerman bombs are associated with photospheric downflows, and their loci follow the transverse mass flows on the photosphere. They are small-scale events, with typical size 18 11 , but this size depends on the instrumental resolution. A large number of Ellerman bombs are probably undetected, owing to limited spatial resolution. Ellerman bombs occur in clusters that exhibit fractal properties. The fractal dimension, with an average value ~1.4, does not change significantly in the course of time. Typical parameters of Ellerman bombs are interrelated and obey power-law distribution functions, as in the case of flaring and subflaring activity. We find that Ellerman bombs may occur on separatrix, or quasi-separatrix, layers, in the low chromosphere. A plausible triggering mechanism of Ellerman bombs is stochastic magnetic reconnection caused by the turbulent evolution of the low-lying magnetic fields and the continuous reshaping of separatrix layers. The total energies of Ellerman bombs are estimated in the range (1027, 1028) ergs, the temperature enhancement in the radiating volume is ~2 103 K, and the timescale of radiative cooling is short, of the order of a few seconds. The distribution function of the energies of Ellerman bombs exhibits a power-law shape with an index ~-2.1. This suggests that Ellerman bombs may contribute significantly to the heating of the low chromosphere in emerging flux regions.
http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2002ApJ...575..506G&db_key=AST&data_type=HTML&format=&high=44cf27c05f22437
Примечания
- Ellerman F. Solar Hydrogen "bombs" (англ.) // Astrophysical Journal. — 1917. — Vol. 46. — P. 298. — doi:10.1086/142366. — .
- http://archives.caltech.edu/search_catalog.cfm?results_file=Detail_View&recsPerPage=1&firstRecToShow=34&search_field=Press&entry_type=photo&photo_id=&cat_series=
Ссылки
Литература- Прист Э. Р. Солнечная магнитогидродинамика. — М.: Мир, 1985. — С. 68.
Категория:Солнечная активность
en:Ellerman bombs
|
|