https://phys.org/news/2018-08-nasa-poised-blast-spacecraft-explore.html

By coming closer to the Sun than any spacecraft in history, the unmanned probe's main goal is to unveil the secrets of the corona, the unusual atmosphere around the Sun.

"We are going to be in an area that is so exciting, where solar wind—we believe—will be accelerating," said NASA planetary science division director Jim Green.