Improved Determination of the Location of the Temperature Maximum in the Corona
View/ Open
Authors
Lemaire, J.F.
Stegen, K.
Discipline
Physical sciences
Audience
Scientific
Date
2016Metadata
Show full item recordDescription
The most used method to calculate the coronal electron temperature [Te(r)] from a coronal density distribution [ne(r)] is the scale-height method (SHM). We introduce a novel method that is a generalization of a method introduced by Alfvén (Ark. Mat. Astron. Fys.27, 1, 1941) to calculate Te(r) for a corona in hydrostatic equilibrium: the “HST” method. All of the methods discussed here require given electron-density distributions [ne(r)] which can be derived from white-light (WL) eclipse observations. The new “DYN” method determines the unique solution of Te(r) for which Te(r→∞)→0 when the solar corona expands radially as realized in hydrodynamical solar-wind models. The applications of the SHM method and DYN method give comparable distributions for Te(r). Both have a maximum [Tmax] whose value ranges between 1 – 3 MK. However, the peak of temperature is located at a different altitude in both cases. Close to the Sun where the expansion velocity is subsonic (r<1.3R⊙) the DYN method gives the same results as the HST method. The effects of the other free parameters on the DYN temperature distribution are presented in the last part of this study. Our DYN method is a new tool to evaluate the range of altitudes where the heating rate is maximum in the solar corona when the electron-density distribution is obtained from WL coronal observations.
Citation
Lemaire, J.F.; Stegen, K. (2016). Improved Determination of the Location of the Temperature Maximum in the Corona. , Solar Physics, Vol. 291, Issue 12, 3659-3683, DOI: 10.1007/s11207-016-1001-3.Identifiers
Type
Article
Peer-Review
Yes
Language
eng