Imagine that I'm designing a space probe, that will initially be placed into an Earth-like orbit around the Sun.
My goal is to have the probe fly/fall into the Sun; it's allowed to take as much time as it needs to do that, as long as it gets there eventually.
Now the hard part: Since the brute-force rocketry-approach to doing this would take a lot of fuel, I'd like my probe to be able to accomplish its goal without using any kind of rockets (except the ones required to get it to its starting position, of course).
Is there a way to do this e.g. by using a solar sail and tacking against the solar wind? If so, how long might that take? (I know the Parker solar probe is using Venus' gravity to help it along, but presumably that technique requires an initial trajectory that will bring it near Venus, which my probe won't have)