I cannot find the right section to post this, anyway I would like to stimulate discussion around a couple of provocative ideas I had.

Intro
After many years of studies, now Solar Sails seems to enter in the real application age: Planetary Society is preparing second tentative to launch it's prototype, while some governative agencies are close to implement space probes pushed by light.
However, I'm convinced that possible applications these object are, by far, wider than simple spacecraft propulsion.
In fact, the great mind of Robert L. Forward conceived a first example of this wider field application throug the "statite" idea: a communication satellite that would use the solar sail to "hover" in a location that would not otherwise be available as a stable geosynchronous orbit.
Russian space agency already tried to use a solar mirror to illuminate high-latitude nightside Earth regions and someone else figured out how to use sails/mirrors to melt Mars polar caps and accelerate terraforming.

Proposals
I propose two other applications of solar sails/mirrors:

1) Attach a sail to a solar wind monitoring satellite, located on the Sun-Earth line, well inside L1 "lagrangian libration point"; this is a position normally unstable, due to Kepler laws... thanks to sail, however, radiation pressure could fill the force gap between increased Sun gravity and reduced centrifugal force.
This should allow strong improvement in the solar storm forecast (an order of magnitude, if sail is located 15 MKm inside Earth orbit). The alerts would arrive a day before, instead of few hours only.

2) Reduce the amount of solar radiation incident on Earth through a flotilla of huge sunshade screens, close to L1 point; this should avoid medium-term consequencies of greenhouse effect, re-establishing energetic balance between incoming and autcoming energy from atmosphere/oceans; the sails can be also moved and re-oriented, in order to CONTROL large scale clima and possibly avoid natural disasters like hurricanes. Obviously, these applications will be possible only if we have very sofisticated and reliable climate models, by far better than today simulations (otherwise, we could cause disasters even grater than those we want to avoid!).
Finally, the energy surplus blocked from these sunshades can be refleced and concentrated toward true solar sail probes, making possible a real exploration of external solar sistem. If energy is used to aliment a mega laser/maser array, this source of coherent, ultra collimated energy can be used to deflect dangerous asteroids or vaporize old satellites/debris in Earth orbit. More sofisticated and larger source could push sails toward interstellar missions...