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<div class="moz-cite-prefix">Hi Phil,<br>
<br>
we have addressed this point in the supplementary material of the
paper,<br>
giving several reasons why we think it's highly unlikely, and the<br>
non-thermal electrons are a much more natural explanation.<br>
<br>
thanks,<br>
Paola<br>
<br>
<br>
On 10/30/14, 9:54 PM, Philip Judge wrote:<br>
</div>
<blockquote
cite="mid:CAOP6=5poAOxRGJh6rwYTzchZmTBaxm=tvREMmxG1sbukpqjVLw@mail.gmail.com"
type="cite">
<p dir="ltr"><br>
If the sun releases 10^25 erg in 30s in the chromosphere, as
needed by these data, cannot this be just local magnetic
heating? A "chromospheric flare"? </p>
<p dir="ltr">Consider magnetic energy density </p>
<p dir="ltr">E= B^2/ 8pi.</p>
<p dir="ltr">In plage let B be say 300G, then E=3e3. Then for
total energy of 10^25 erg we need 3e21 cm3 and d^3=V gives
length d of 10^7 cm, or 0.1 Mm. If I use rho= 1e-10 g for mid
chromosphere, then the alfven speed v_a is 80 kms and d/v_a is
1.2 sec. Fast.</p>
<p dir="ltr">So I am really puzzled why you appeal to beams at
all. There is certainly nothing in the iris data that I can see
could ever be used to give direct evidence for e- beams... all
I can glean from these data is that there is a sudden release of
energy under the place where Si IV is formed.</p>
<p dir="ltr">So I am very puzzled...</p>
<p dir="ltr">Philip Judge, Scientist, HAO, NCAR<br>
3037759863 <br>
</p>
<div class="gmail_quote">On Oct 30, 2014 2:49 PM, "Paola Testa"
<<a moz-do-not-send="true"
href="mailto:ptesta@cfa.harvard.edu">ptesta@cfa.harvard.edu</a>>
wrote:<br type="attribution">
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000"> Dear all,<br>
<br>
you might be interested in the following paper that has just
been published on Science:<br>
"Evidence of non-thermal particles in coronal loops heated
impulsively by nanoflares"<br>
It can be downloaded from astro-ph: <a
moz-do-not-send="true"
href="http://arxiv.org/abs/1410.6130" target="_blank">http://arxiv.org/abs/1410.6130</a>
or directly<br>
from the Science pages: <a moz-do-not-send="true"
href="http://www.sciencemag.org/content/346/6207/1255724"
target="_blank">http://www.sciencemag.org/content/346/6207/1255724</a><br>
The abstract is below.<br>
<br>
cheers,<br>
Paola<br>
<br>
<br>
Abstract:<br>
The physical processes causing energy exchange between the
Sun’s hot corona and its<br>
cool lower atmosphere remain poorly understood. The
chromosphere and transition region<br>
(TR) form an interface region between the surface and the
corona that is highly sensitive to<br>
the coronal heating mechanism. High-resolution observations
with the Interface Region<br>
Imaging Spectrograph (IRIS) reveal rapid variability (~20 to
60 seconds) of intensity and<br>
velocity on small spatial scales (≲500 kilometers) at the
footpoints of hot and dynamic<br>
coronal loops. The observations are consistent with
numerical simulations of heating by<br>
beams of nonthermal electrons, which are generated in small
impulsive (≲30 seconds)<br>
heating events called “coronal nanoflares.” The accelerated
electrons deposit a sizable<br>
fraction of their energy (≲10^25 erg) in the chromosphere
and TR. Our analysis provides tight<br>
constraints on the properties of such electron beams and new
diagnostics for their<br>
presence in the nonflaring corona.<br>
<br>
</div>
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</blockquote>
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</blockquote>
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