Determining coronal heating of plasma loops through differential emission measure analysis

Abstract

Insights into the nature of the heating mechanism in coronal plasmas can be gained through the analysis of differential emission measure curves localized along coronal loops. This technique is especially desirable since it does not require the isothermal approximation for potentially dynamic loop plasmas. Of particular interest are the parameters describing the heating rate per unit volume in the corona as a function of radial height and/or arc length along loop structures. Using simultaneous observations taken on 20 April 98 with the Solar and Heliospheric Observatory Coronal Diagnostics Spectrometer and the Yohkoh Soft X-ray Telescope, plasma temperature distributions were constructed in the relevant temperature domain (Log T = 5.5–7.5) along an isolated coronal loop on the west limb, ranging from one footpoint to the loop top. Subsequent analysis of the differential emission measure curves using abundance values from Fludra and Schmelz (1999) at each pixel combined with knowledge of the loop geometry helped to pin down the coronal heating mechanism using the method described by Priest et al. (1998).