HR: 13:30h
AN: SP13B-01 [Abstracts]
TI: Dissertation talk: The EUV Unresolved Corona and Coronal Loops
AU: * Cirtain, J
EM: jcirtain@cfa.harvard.edu
AF: Montana State University, 264 EPS, Bozeman, MT 59717 United States
AU: * Cirtain, J
EM: jcirtain@cfa.harvard.edu
AF: Harvard-Smothsonian Astophysical Observatory, 60 Garden St.
Mail stop 56, Cambridge, MA 02138 United States
AB:
In this work, physical characteristics of the solar corona in the Extreme Ultra-Violet (EUV) regime of the electromagnetic
spectrum are investigated. Regions of heightened coronal activity are generally
found near the locations of sunspots. These regions are commonly called
Active Regions and are the focus of the project. Multiple space
based observing platforms have been deployed in the last decade and
it is possible to use several of these observatories in combination to develop a
more complete picture of the solar corona. Joint Observing Program 146 was
created to collect spectroscopic intensities using the Coronal
Diagnostic Spectrometer (CDS) on Solar and Heliospheric Observatory
(SoHO) and EUV images using NASA's
Transition Region and Coronal Explorer (TRACE).
The emission line intensities are used to
develop an understanding of the temperature and density of the active
region coronal plasma. However, the performance of the
CDS instrument in the spatial and temporal domains is limited and to
compensate for these limitations data collected by the TRACE
instrument provide a high spatial and temporal resolution set of
observations. The combination of the information contained in the data
from these two instruments is used to determine the temperature,
density and dynamics of the solar coronal active regions.
One of the most exciting unsolved problems in solar astrophysics is
to understand why the corona maintains a temperature roughly two orders of
magnitude higher than the underlying material. An detailed investigation of the
coronal emission has provided constraints on models of the heating mechanism, since the
temperature, density and evolution of emission
rates for multiple ionic species are indicative of the mechanism(s)
working to heat the corona. The observed corona appears to consist of multiple
unresolved structures as well as resolved active region structures, called
coronal loops. The purpose of the present work is to determine the
characteristics of the unresolved background corona. This has two
important applicatons. Any model of the corona must account for the
emission comprising the unresolved background, and the study
of coronal loops can be improved by subtracting the emission along the
line-of-sight due to the background contribution to the total intensity. Using the characterizations
of the coronal unresolved background, results for loops after
background subtraction are also presented. This work demostrates the
magnitude of the unresolved coronal emission with respect to the total
emission along the line of sight, and how this compares to that of the
resolved loops. It is apparent from this analyis that the unresolved
corona is the dominant source of radiation in the active region corona.
DE: 7509 Corona
DE: 7549 Ultraviolet emissions
SC: Solar Physics Division - AAS [SP]
MN: 2005 Joint Assembly