Why is the Solar Corona So Hot?
This fundamental question has challenged space scientists for decades. At temperatures of several million degrees, the corona is hundreds of times hotter than the solar surface, so heat cannot simply flow upward against the temperature gradient. (The same is true on other stars.) It is widely believed that the energy responsible for the extreme temperatures is extracted from the stressed magnetic fields that permeate the corona. The details of how this occurs are still, however, a matter of vigorous debate. Finding the answer is more than just a fascinating intellectual exercise. X-ray and UV radiation from the corona is an important driver of the Earth’s upper atmosphere. In this talk, I will review our current understanding of the coronal heating problem and discuss exciting recent advances.