Spectral Contrast in Chromospheric Quiescent Emission

Abstract:

Quiescent conditions are not easily distinguishable from each other in integrated chromospheric emission, especially when they are underlying different coronal structures or are neighboring different large scale magnetic configurations. In this study we are using datasets from the Interface Region Imaging Spectrograph (IRIS) to investigate the statistical properties of such 'quiet' emission in order to identify those observables that can be used to differentiate such regions. We developed and employed a fast profile features identification algorithm for the Mg II resonance lines emission, to probe the chromospheric contrast based on different Mg II spectral features. The correlation between these spectroscopic measurements is discussed in the context of their relation to each other and to the emitting plasma. Overall, the Inter-network regime is dominated by signatures of convective motions, which become suppressed in the Network, where the magnetic field leads to increased emission. We found that the line width and peak separation are enhanced under coronal holes compared to the other conditions considered, while the other measurement are only marginally sensitive.