Published online by Cambridge University Press: 03 August 2017
Continuum observations in the far IR have given us a broad spectrum of new and powerful diagnostic utilities for the solar atmosphere. The infrared continuum is formed in LTE with thermal free electrons by free-free interactions. This gives us a flexible and accurate atmospheric thermometer that has made infrared measurements fundamental to modeling of the quiet solar medium for more than two decades. The submillimeter and millimeter continua are particularly useful with respect to thermal diagnostics of the low chromospheric temperature minimum, where non-radiative heating of the solar medium becomes clearly manifest. Modern submillimeter telescopes and instrumentation on Mauna Kea, in Hawaii, are now revolutionizing solar observations in the submillimeter spectrum, giving us the first observations of detail on the scale of the chromospheric supergranular network, sunspots and prominences. These observations are showing us a remarkable and unexpected view of thermal structure that emerges as one probes to successively higher levels above the chromospheric temperature minimum.