Folks,
I submitted the following paper to ApJ and put a copy on Astro-Ph:
Article-id: 0804.2241. Its main purpose was to develop the tools
for rapid forward modeling of loops observed by XRT and AIA.
Best regards,
Piet
Scaling Laws and Temperature Profiles for Solar and Stellar Coronal
Loops with Non-uniform Heating
P.C.H. Martens
Abstract:
The bulk of solar coronal radiative loss consists of soft X-ray emission
from quasi-static loops at the cores of Active Regions. In …
[View More]order to
develop diagnostics for determining the heating mechanism of these loops
from observations by coronal imaging instruments, I have developed
analytical solutions for the temperature structure and scaling laws of
loop strands for a wide range of heating functions, including footpoint
heating, uniform heating, and heating concentrated at the loop apex. Key
results are that the temperature profile depends only weakly on the
heating distribution -- not sufficiently to be of significant diagnostic
value -- and that the scaling laws survive for this wide range of
heating distributions, but with the constant of proportionality in the
RTV scaling law ($P_{0}L\, \thicksim\, T_{max}^3$) depending on the
specific heating function. Furthermore, quasi-static analytical
solutions do not exist for an excessive concentration of heating near
the loop footpoints, a result in agreement with recent numerical
simulations. It is demonstrated that a generalization of the solutions
to the case of a strand with a variable diameter leads to only
relatively small correction factors in the scaling laws and temperature
profiles for constant diameter loop strands. A quintet of leading
theoretical coronal heating mechanisms is shown to be captured by the
formalism of this paper, and the differences in thermal structure
between them may be verified through observations. Preliminary results
from full numerical simulations demonstrate that, despite the
simplifying assumptions, the analytical solutions from this paper are
stable and accurate.
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Piet Martens Tel: 617-496-7769
Center for Astrophysics Fax: 617-496-7577
60 Garden Street, MS 58 Cell: 617-999-0353
Cambridge, MA 02138 pmartens(a)cfa.harvard.edu
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