Hi. Just because we study the Sun does not mean we know much about solar sails! It has been a couple days, though, and no-one has replied, so I will just say that the interesting thing for me related to solar sails is that they could give us the ability to be spacecraft in different locations and orbits than we can now.
At this point we usually have to have the spacecraft orbiting around a planet or the sun, but a solar sail might make it possible to just "sit" over the poles of the Sun or a planet.
That could be a very useful place to be if you wanted to study the Sun's poles, for instance.
That sort of capability probably won't be available very soon though.
A little more information:
http://www.esa.int/Education/Solar_sails Terry