[Loops] Loop Temperature Paper Accepted

[Petrus Martens]

Folks,

    The paper linked below has been resubmitted and accepted by ApJ,
after languishing for too long in my desk drawer.  It is scheduled
for publication in May, v 714.

Title: "Scaling Laws and Temperature Profiles for Solar and Stellar
Coronal Loops with Non-uniform Heating"

Author: P.C.H. Martens1
Department of Physics. Montana State University – Bozeman
martens at physics.montana.edu
1Smithsonian Research Associate, Smithsonian Astrophysical
Observatory

URL: 
http://solar.physics.montana.edu/martens/papers/v3+proofs-apjformat.pdf

    Cheers,

    Piet


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 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 set of temperature and pressure dependent heating 
functions that encompass heating concentrated at the footpoints, 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 (P0L ~ 
T3max) depending on the specific heating function. Furthermore, quasi- 
static 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 results to 
a set of solutions for strands with a functionally prescribed 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 accurate and stable.

Subject headings: Sun: chromosphere — Sun: corona — hydrodynamics

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