A Comprehensive Model of the K-coronal Spectrum for the Inference of Electron Temperature and Bulk Flow Velocity in the Corona

Abstract

The electron temperature of the corona is one of the key physical parameters which reflect the complexity of coronal-heating processes. L. E. Cram was the first to show that the K-coronal spectrum, produced by the scattering of the photospheric spectrum from free streaming coronal electrons, could be used to infer the coronal temperature with an uncertainty of 0.2 MK. This study revisits Cram's original work by introducing a robust mathematical model which enables the exploration of a broad range of plasma parameters, most importantly the electron velocity distribution, in its implementation. While the inference of electron temperature is well established, the model results show that the velocity of the electrons in the inner corona can also be inferred.