Can the Differential Emission Measure constrain the timescale of energy deposition

TL;DR

This study assesses the Hinode/EIS instrument's capability to use Differential Emission Measure (DEM) analysis to distinguish between different coronal heating mechanisms by evaluating the uncertainties in DEM slope measurements.

Contribution

It provides a detailed analysis of the uncertainties in DEM slope measurements and their implications for diagnosing coronal heating timescales.

Findings

DEM slope uncertainty depends on the number of spectral lines used.

Typical uncertainty in DEM slope is about ±1.0 in favorable cases.

Proper uncertainty estimation is crucial for interpreting DEM diagnostics.

Abstract

In this paper, the ability of the Hinode/EIS instrument to detect radiative signatures of coronal heating is investigated. Recent observational studies of AR cores suggest that both the low and high frequency heating mechanisms are consistent with observations. Distinguishing between these possibilities is important for identifying the physical mechanism(s) of the heating. The Differential Emission Measure (DEM) tool is one diagnostic that allows to make this distinction, through the amplitude of the DEM slope coolward of the coronal peak. It is therefore crucial to understand the uncertainties associated with these measurements. Using proper estimations of the uncertainties involved in the problem of DEM inversion, we derive confidence levels on the observed DEM slope. Results show that the uncertainty in the slope reconstruction strongly depends on the number of lines constraining the slope. Typical uncertainty is estimated to be about $\pm 1.0$, in the more favorable cases.