Radial Distributions of Coronal Electron Temperatures: specificities of the DYN model. (arXiv:2002.07495v3 [astro-ph.SR] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Lemaire_J/0/1/0/all/0/1">Joseph F. Lemaire</a> (1 and 2), <a href="http://arxiv.org/find/astro-ph/1/au:+Katsiyannis_A/0/1/0/all/0/1">Athanassios C. Katsiyannis</a> (3) ((1) Universite Catholique de Louvain, (2) Royal Belgian Institute for Space Aeronomy, (3) Royal Observatory of Belgium)
This paper is a follow up of the article where Lemaire and Stegen (2016)
introduced their DYN method to calculate coronal temperature profiles from
given radial distributions of the coronal and solar wind (SW) electron
densities. Several such temperature profiles are calculated and presented
corresponding to a set of given empirical density models derived from eclipse
observations and in-situ measurements of the electron density and bulk velocity
at 1 AU. The DYN temperature profiles obtained for the equatorial and polar
regions of the corona challenge the results deduced since 1958 from singular
hydrodynamical models of the SW. In these models – where the expansion velocity
transits through a singular saddle point – the maximum coronal temperature is
predicted to be located at the base of the corona, while in all DYN models the
altitude of the maximum temperature is found at significantly higher altitudes
in the mid-corona. Furthermore, the maximum of the DYN-estimated temperatures
is found at much higher altitudes over the polar regions and coronal holes,
than over the equator. However, at low altitudes, in the inner corona, the DYN
temperatures are always smaller at high latitudes, than at low equatorial
latitudes. This appears well in agreement with existing coronal hole
observations. These findings have serious implications on the open questions:
what is the actual source of the coronal heating, and where is the maximum
energy deposited within the solar corona?
This paper is a follow up of the article where Lemaire and Stegen (2016)
introduced their DYN method to calculate coronal temperature profiles from
given radial distributions of the coronal and solar wind (SW) electron
densities. Several such temperature profiles are calculated and presented
corresponding to a set of given empirical density models derived from eclipse
observations and in-situ measurements of the electron density and bulk velocity
at 1 AU. The DYN temperature profiles obtained for the equatorial and polar
regions of the corona challenge the results deduced since 1958 from singular
hydrodynamical models of the SW. In these models – where the expansion velocity
transits through a singular saddle point – the maximum coronal temperature is
predicted to be located at the base of the corona, while in all DYN models the
altitude of the maximum temperature is found at significantly higher altitudes
in the mid-corona. Furthermore, the maximum of the DYN-estimated temperatures
is found at much higher altitudes over the polar regions and coronal holes,
than over the equator. However, at low altitudes, in the inner corona, the DYN
temperatures are always smaller at high latitudes, than at low equatorial
latitudes. This appears well in agreement with existing coronal hole
observations. These findings have serious implications on the open questions:
what is the actual source of the coronal heating, and where is the maximum
energy deposited within the solar corona?
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