1 research outputs found
Modeling Evolving Coronal Loops with Observations from STEREO, Hinode, and TRACE
The high densities, long lifetimes, and narrow emission measure distributions
observed in coronal loops with apex temperatures near 1 MK are difficult to
reconcile with physical models of the solar atmosphere. It has been proposed
that the observed loops are actually composed of sub-resolution ``threads''
that have been heated impulsively and are cooling. We apply this heating
scenario to nearly simultaneous observations of an evolving post-flare loop
arcade observed with the EUVI/\textit{STEREO}, XRT/\textit{Hinode}, and
\textit{TRACE} imagers and the EIS spectrometer on \textit{HINODE}. We find
that it is possible to reproduce the extended loop lifetime, high electron
density, and the narrow differential emission measure with a multi-thread
hydrodynamic model provided that the time scale for the energy release is
sufficiently short. The model, however, does not reproduce the evolution of the
very high temperature emission observed with XRT. In XRT the emission appears
diffuse and it may be that this discrepancy is simply due to the difficulty of
isolating individual loops at these temperatures. This discrepancy may also
reflect fundamental problems with our understanding of post-reconnection
dynamics during the conductive cooling phase of loop evolution.Comment: Revised version submitted to ApJ in response to referee's comment