The interrelation of hard X-ray (HXR) emitting sources and the underlying
physics of electron acceleration and transport presents one of the major
questions in the high energy solar flare physics. Spatially resolved
observations of solar flares often demonstrate the presence of well separated
sources of bremsstrahlung emission, so-called coronal and foot-point sources.
Using spatially resolved X-ray observations by the Reuven Ramaty High Energy
Solar Spectroscopic Imager (RHESSI) and recently improved imaging techniques,
we investigate in detail the spatially resolved electron distributions in a few
well observed solar flares. The selected flares can be interpreted as having a
standard geometry with chromospheric HXR foot-point sources related to
thick-target X-ray emission and the coronal sources characterised by a
combination of thermal and thin-target bremsstrahlung. Using imaging
spectroscopy technique, we deduce the characteristic electron rates and
spectral indices required to explain the coronal and foot-points X-ray sources.
We found that, during the impulsive phase, the electron rate at the loop-top is
several times (a factor of 1.7-8) higher than at the foot-points. The results
suggest sufficient number of electrons accelerated in the loop-top to explain
the precipitation into the foot-points and implies electrons accumulation in
the loop-top. We discuss these results in terms of magnetic trapping,
pitch-angle scattering and injection properties. Our conclusion is that the
accelerated electrons must be subject to magnetic trapping and/or pitch-angle
scattering, keeping a fraction of the population trapped inside the coronal
loops. These findings put strong constraints on the particle transport in the
coronal source, and provide a quantitative limits on deka-keV electron
trapping/scattering in the coronal source.
%0 Generic
%1 citeulike:11981698
%A Sim\ oes, Paulo J. A.
%A Kontar, Eduard P.
%D 2013
%K imported
%T Implications for electron acceleration and transport from non-thermal electron rates at loop-top and foot-point sources in solar flares
%U http://arxiv.org/abs/1301.7591
%X The interrelation of hard X-ray (HXR) emitting sources and the underlying
physics of electron acceleration and transport presents one of the major
questions in the high energy solar flare physics. Spatially resolved
observations of solar flares often demonstrate the presence of well separated
sources of bremsstrahlung emission, so-called coronal and foot-point sources.
Using spatially resolved X-ray observations by the Reuven Ramaty High Energy
Solar Spectroscopic Imager (RHESSI) and recently improved imaging techniques,
we investigate in detail the spatially resolved electron distributions in a few
well observed solar flares. The selected flares can be interpreted as having a
standard geometry with chromospheric HXR foot-point sources related to
thick-target X-ray emission and the coronal sources characterised by a
combination of thermal and thin-target bremsstrahlung. Using imaging
spectroscopy technique, we deduce the characteristic electron rates and
spectral indices required to explain the coronal and foot-points X-ray sources.
We found that, during the impulsive phase, the electron rate at the loop-top is
several times (a factor of 1.7-8) higher than at the foot-points. The results
suggest sufficient number of electrons accelerated in the loop-top to explain
the precipitation into the foot-points and implies electrons accumulation in
the loop-top. We discuss these results in terms of magnetic trapping,
pitch-angle scattering and injection properties. Our conclusion is that the
accelerated electrons must be subject to magnetic trapping and/or pitch-angle
scattering, keeping a fraction of the population trapped inside the coronal
loops. These findings put strong constraints on the particle transport in the
coronal source, and provide a quantitative limits on deka-keV electron
trapping/scattering in the coronal source.
@misc{citeulike:11981698,
abstract = {{The interrelation of hard X-ray (HXR) emitting sources and the underlying
physics of electron acceleration and transport presents one of the major
questions in the high energy solar flare physics. Spatially resolved
observations of solar flares often demonstrate the presence of well separated
sources of bremsstrahlung emission, so-called coronal and foot-point sources.
Using spatially resolved X-ray observations by the Reuven Ramaty High Energy
Solar Spectroscopic Imager (RHESSI) and recently improved imaging techniques,
we investigate in detail the spatially resolved electron distributions in a few
well observed solar flares. The selected flares can be interpreted as having a
standard geometry with chromospheric HXR foot-point sources related to
thick-target X-ray emission and the coronal sources characterised by a
combination of thermal and thin-target bremsstrahlung. Using imaging
spectroscopy technique, we deduce the characteristic electron rates and
spectral indices required to explain the coronal and foot-points X-ray sources.
We found that, during the impulsive phase, the electron rate at the loop-top is
several times (a factor of 1.7-8) higher than at the foot-points. The results
suggest sufficient number of electrons accelerated in the loop-top to explain
the precipitation into the foot-points and implies electrons accumulation in
the loop-top. We discuss these results in terms of magnetic trapping,
pitch-angle scattering and injection properties. Our conclusion is that the
accelerated electrons must be subject to magnetic trapping and/or pitch-angle
scattering, keeping a fraction of the population trapped inside the coronal
loops. These findings put strong constraints on the particle transport in the
coronal source, and provide a quantitative limits on deka-keV electron
trapping/scattering in the coronal source.}},
added-at = {2019-03-25T08:20:55.000+0100},
archiveprefix = {arXiv},
author = {Sim\ {o}es, Paulo J. A. and Kontar, Eduard P.},
biburl = {https://www.bibsonomy.org/bibtex/2521e5e3500735f4713881a636ba80e81/ericblackman},
citeulike-article-id = {11981698},
citeulike-linkout-0 = {http://arxiv.org/abs/1301.7591},
citeulike-linkout-1 = {http://arxiv.org/pdf/1301.7591},
day = 31,
eprint = {1301.7591},
interhash = {f88f6cb48d4a043903b10055339e8914},
intrahash = {521e5e3500735f4713881a636ba80e81},
keywords = {imported},
month = jan,
posted-at = {2013-02-03 01:19:22},
priority = {2},
timestamp = {2019-03-25T08:20:55.000+0100},
title = {{Implications for electron acceleration and transport from non-thermal electron rates at loop-top and foot-point sources in solar flares}},
url = {http://arxiv.org/abs/1301.7591},
year = 2013
}