Exploring Mutual Information between IRIS Spectral Lines. II. Calculating the Most Probable Response in all Spectral Windows

A three-dimensional picture of the solar atmosphere's thermodynamics can be obtained by jointly analyzing multiple spectral lines that span many formation heights. In Paper I, we found strong correlations between shapes from a variety different ions during flares in comparison to quiet Sun. We extend these techniques address following questions: which regions atmosphere are most connected flare, and what likely responses across several windows based on observation single Mg ii spectrum? Our models derived million IRIS spectra collected 21 M- X-class flares. applied this framework archetypal flare analyzed results multiline perspective. find (1) line photosphere transition region highest ribbons. (2) Blueshifted reversals appear simultaneously ii, C Si iv impulsive phase, with displaying possible optical depth effects. Fe shows signs emission, indicating deep early heating. (3) The appears typically evolve blueshifted reversal later returns center becomes peaked within 1–3 minutes. widths single-peaked profiles slowly erode time. During stages, red-wing enhancements coronal rain evident iv. is easily adaptable any data set enables comprehensive statistical analyses atmospheric behavior windows.