Is It Small-scale, Weak Magnetic Activity That Effectively Heats the Upper Solar Atmosphere?

Solar chromosphere and coronal heating are big questions for astrophysics. Daily measurement of 985 solar spectral irradiances (SSIs) at the spectral intervals 1-39 nm and 116-2416 nm during 2003 March 1 to 2017 October 28 are utilized to investigate phase relation with respect to daily sunspot number, the Mount Wilson sunspot Index, and the Magnetic Plage Strength Index. All the SSIs form in the abnormally heated layer; the upper photosphere, chromosphere, transition region, and corona are found to be significantly more correlated to weak magnetic activity than to strong magnetic activity, and are found to dance in step with weak magnetic activity. All the SSIs that form in the low photosphere, which indicate the "energy" leaked from the solar subsurface, are found to be more related to strong magnetic activity instead and in anti-phase with weak magnetic activity. In the upper photosphere and chromosphere, strong magnetic activity should lead SSI by about a solar rotation, which also implies that weak magnetic activity should take effect from heating there. It is thus small-scale weak magnetic activity that effectively heats the upper solar atmosphere.