why wouldn't this work with a plasma field? If you inflate your leading edge to be larger, your net solar wind flux is going to be larger and a greater amount of force will be transferred to the craft from the leading edge, slowing you down. Even though you're being pushed OUT by the solar wind, your tangential velocity relative to the sun will be reduced, which, even if it results in a greater net orbital energy, will result in a more elliptical orbit (and thus a trajectory that sends you inwards).