  There is currently no explanation of why the corona has the temperature and
density it has. We present a model which explains how the dynamics of magnetic
reconnection regulates the conditions in the corona. A bifurcation in magnetic
reconnection at a critical state enforces an upper bound on the coronal
temperature for a given density. We present observational evidence from 107
flares in 37 sun-like stars that stellar coronae are near this critical state.
The model may be important to self-organized criticality models of the solar
corona.
