TY - JOUR
T1 - Maps of the Coronal Electron Density Distribution at Solar Maximum - Estimates Based on LASCO Observations
AU - Morgan, Huw
AU - Habbal, Shadia Rifai
N1 - American Astronomical Society Meeting 210, #105.03; Bulletin of the American Astronomical Society, Vol. 39, p.231
PY - 2007/5/1
Y1 - 2007/5/1
N2 - Estimating the 3D distribution of electron density from a set of 2D
white light observations is a critical challenge in coronal physics.
Such an estimation is difficult during solar maximum due to rapid
structural changes in the corona, and to the frequent `contamination' of
observations by transient event. The primary aim of this work is to
create global maps of electron density for Carrington Rotation 1953
which provide reasonable agreement with polarized brightness observed by
the LASCO C2 coronagraph. The technique is based on a solar rotational
tomography technique, and while the densities contained within the
initially created maps are in arbitrary units, we assume that it gives a
reasonable estimate of the 3D spatial distribution, or position, of
density structures. A smaller set of LASCO polarized brightness
observations are then used as a constraint in a least-squares fitting
routine to improve the agreement between observation and model. This
step also converts the density map from arbitrary to electron density
units. Given the rapid structural changes of the solar maximum corona,
our static estimate of electron density gives reasonable agreement with
polarized brightness observations. Improvements to the technique will be
discussed.
AB - Estimating the 3D distribution of electron density from a set of 2D
white light observations is a critical challenge in coronal physics.
Such an estimation is difficult during solar maximum due to rapid
structural changes in the corona, and to the frequent `contamination' of
observations by transient event. The primary aim of this work is to
create global maps of electron density for Carrington Rotation 1953
which provide reasonable agreement with polarized brightness observed by
the LASCO C2 coronagraph. The technique is based on a solar rotational
tomography technique, and while the densities contained within the
initially created maps are in arbitrary units, we assume that it gives a
reasonable estimate of the 3D spatial distribution, or position, of
density structures. A smaller set of LASCO polarized brightness
observations are then used as a constraint in a least-squares fitting
routine to improve the agreement between observation and model. This
step also converts the density map from arbitrary to electron density
units. Given the rapid structural changes of the solar maximum corona,
our static estimate of electron density gives reasonable agreement with
polarized brightness observations. Improvements to the technique will be
discussed.
UR - http://hdl.handle.net/2160/9226
M3 - Meeting Abstract
SN - 0002-7537
VL - 39
SP - 231
JO - Bulletin of the American Astronomical Society
JF - Bulletin of the American Astronomical Society
ER -