Fredagskollokvium: Eamon Scullion: Towards Understanding The Solar Coronal Cooling Problem
Eamon Michael Scullion, postdoktor, Institutt for teoretisk astrofysikk
In solar physics, we are all very familiar with the long-standing solar coronal heating problem. The outer atmosphere (corona) of our closest star is hotter than expected (by approx. 3 orders of magnitude on average) and the physical mechanisms for injecting energetic plasma into this region are numerous. In light of this problem, over the past 15-20 years significant advances in our observing capabilities have revealed an increasingly complex interaction between the different layers of the solar atmosphere. Consequently, it is plausible that no *single* theory for widespread coronal heating dominates. What gets less attention is what happens *after* the heating processes inject the corona with hot plasma. Does the hot material escape into the solar wind stream or fall-back or become a composite of the coronal environment (?). We suggest that to gain further insight into coronal heating one must consider how the corona regulates this heating. In this talk, I will first discuss how we are now able to utilize multiple solar observing facilities for gathering more data across a broader spectral range, hence, gain a deeper understanding of the interactions between the cool and hot solar atmosphere. Ultimately, I will focus on our recent observational analysis, revealing the formation of a catastrophic cooling process in the corona, leading to the draining of the corona in the form of dense cold plasma (fall-back). The implications for this will be discussed briefly in the context of thermal equilibrium vs. thermal non-equilibrium models of the solar corona.