Hui Tian, Scott W. McIntosh, Lidong Xia, Jiansen He, Xin Wang
We analyze several data sets obtained by Hinode/EIS and find various types of
flows during CMEs and EUV jet eruptions. CME-induced dimming regions are found
to be characterized by significant blueshift and enhanced line width by using a
single Gaussian fit. While a red-blue (RB) asymmetry analysis and a RB-guided
double Gaussian fit of the coronal line profiles indicate that these are likely
caused by the superposition of a strong background emission component and a
relatively weak (~10%) high-speed (~100 km s-1) upflow component. This finding
suggests that the outflow velocity in the dimming region is probably of the
order of 100 km s-1, not ~20 km s-1 as reported previously. Density and
temperature diagnostics suggest that dimming is primarily an effect of density
decrease rather than temperature change. The mass losses in dimming regions as
estimated from different methods are roughly consistent with each other and
they are 20%-60% of the masses of the associated CMEs. With the guide of RB
asymmetry analysis, we also find several temperature-dependent outflows (speed
increases with temperature) immediately outside the (deepest) dimming region.
In an erupted CME loop and an EUV jet, profiles of emission lines formed at
coronal and transition region temperatures are found to exhibit two
well-separated components, an almost stationary component accounting for the
background emission and a highly blueshifted (~200 km s-1) component
representing emission from the erupting material. The two components can easily
be decomposed through a double Gaussian fit and we can diagnose the electron
density, temperature and mass of the ejecta. Combining the speed of the
blueshifted component and the projected speed of the erupting material derived
from simultaneous imaging observations, we can calculate the real speed of the
ejecta.
View original:
http://arxiv.org/abs/1201.2204
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