Документ взят из кэша поисковой машины. Адрес
оригинального документа
: http://www.izmiran.rssi.ru/~ichertok/Dimming/4l_abstract.html
Дата изменения: Wed Mar 12 11:06:20 2003 Дата индексирования: Sun Apr 10 01:20:06 2016 Кодировка: Поисковые слова: п п п п п п п п п п |
Dimmings or transient coronal holes (i.e.
regions of decreased intensity of soft X-ray and EUV emission), which are
observed on the solar disk after halo coronal mass ejections (CMEs), are
analyzed using SOHO/EIT data simultaneously in three coronal lines Fe IX/X
(171 A), Fe XII (195 A) and Fe IX (284 A) sensitive to temperatures Te~1.2,
1.5 and 2.0 MK, respectively, as well as in the transition region line
He II (304 A; Te~(0.02-0.08) MK). The analysis of rerotated difference
images with 6- or 12-hour intervals and prior compensation of the solar
rotation shows that usually the dimmings are most pronounced and have similar
large-scale structures in the moderate-temperature coronal lines 171 and
195 A, while in the higher-temperature 284 A line the deepest dimming fragments
are mainly visible. Many on-disk CME events show also clear, but relatively
small-area dimming manifestations in 304 A line particularly at the background
regions joining to a main eruption source. Moreover, there are events displaying
transition region dimming patches that have no dimming counterparts in
the coronal lines. These results suggest that in course of a CME process,
opening of the magnetic field lines resulting in density depletion can
also extend into cooler plasma of the transition region. Effects of temperature
variations also cannot be ruled out for some dimming structures.