January 27, 2012, 12:00 pm - 1:00 pm

January 27, 12:00 pm - 1:00 pm

Radiative Heating of the Sun's Corona

Dr. Thomas Moran, NASA GSFC/Catholic University

The atmosphere surrounding the Sun known as the corona has a temperature of 2,000,000 K, a factor of 200 higher than that of the photosphere. Therefore, the corona must be heated by a nonconductive mechanism. We consider the possibility that some portion of this heating is provided by sunlight in the visible and infrared and test this idea though a Monte-Carlo simulation of the wave-particle interaction. We conclude that sunlight provides at least 40% and possibly all of the power required to heat the corona, with the exception of the dense magnetic flux loops. Coronal electrons are heated in a stochastic manner by low-coherence, solar electromagnetic radiation. The low coherence of solar radiation allows moving electrons to gain energy from the chaotic wave field, which imparts multiple random velocity `kicks' to these particles causing their velocity distribution to broaden or heat at levels required to balance radiative losses. We propose to test this model through a laboratory experiment, confining electrons in a Penning trap, illuminating them with low coherence broadband visible and infrared light and measuring the resulting heating for comparision with our predictions. This experiment could determine whether sunlight heats the corona outside of dense flux loops.