Page "Corona" Paragraph 19

Coronal loops have become very important when trying to understand the current coronal heating problem.

Coronal loops are highly radiating sources of plasma and therefore easy to observe by instruments such as TRACE ; they are highly observable laboratories to study phenomena such as solar oscillations, wave activity and nanoflares.

However, it remains difficult to find a solution to the coronal heating problem as these structures are being observed remotely, where many ambiguities are present ( i. e. radiation contributions along the LOS ).

In-situ measurements are required before a definitive answer can be arrived at, but due to the high plasma temperatures in the corona, in-situ measurements are impossible ( at least for the time being ).

The next mission of the Nasa Solar Probe Plus will approach the Sun very closely allowing more direct observations.