Solar Active Region Heating Diagnostics from High Temperature Emission using the Marshall Grazing Incidence X-ray Spectrometer (MaGIXS)

TL;DR

This paper demonstrates that high-temperature X-ray spectral line ratios, especially from MaGIXS, are effective diagnostics for determining the frequency of coronal heating in solar active regions, validated through modeling and comparison with other instruments.

Contribution

It introduces a simple spectral line ratio diagnostic using MaGIXS data to distinguish between high and low frequency coronal heating, validated by numerical modeling.

Findings

MaGIXS line ratios effectively diagnose heating frequency.

FOXSI and AIA channels also sensitive to heating frequency.

Model comparisons confirm MaGIXS diagnostic accuracy.

Abstract

The relative amount of high temperature plasma has been found to be a useful diagnostic to determine the frequency of coronal heating on sub-resolution structures. When the loops are infrequently heated, a broad emission measure (EM) over a wider range of temperatures is expected. A narrower EM is expected for high frequency heating where the loops are closer to equilibrium. The soft X-ray spectrum contains many spectral lines that provide high temperature diagnostics, including lines from Fe XVII-XIX. This region of the solar spectrum will be observed by the Marshall Grazing Incidence Spectrometer (MaGIXS) in 2020. In this paper, we derive the expected spectral lines intensity in MaGIXS to varying amounts of high temperature plasma to demonstrate that a simple line ratio of these provides a powerful diagnostic to determine the heating frequency. Similarly, we examine ratios of AIA channel intensities, filter ratios from a XRT, and energy bands from the FOXSI sounding rocket to determine their sensitivity to this parameter. We find that both FOXSI and MaGIXS provide good diagnostic capability for high-temperature plasma. We then compare the predicted line ratios to the output of a numerical model and confirm the MaGIXS ratios provide an excellent diagnostic for heating frequency.