An old NASA news article I came across states that a solar flare observed in 2002 produced around a half-kilo of antimatter:

<https://www.nasa.gov/vision/universe/solarsystem/rhessi_antimatter.html>

How realistic would it be to harvest the antimatter from a solar flare? Presumably, a mission to obtain the antimatter (with the intention of using it to power an interstellar spacecraft) would need to overcome some of the following obstacles:

1. Survival: the spacecraft and harvesting apparatus would need to be able to withstand violent, high-temperature conditions.
2. Prediction: the spacecraft would need to be located in a region where a solar flare is likely to happen, before it happens (presumably near a sunspot), and then to stand idly by for a period of months (or even years) waiting for a flare.
3. Collection: the harvesting apparatus would need to somehow isolate the stream of antiparticles released in the solar flare (perhaps using very strong magnets), collect them into storage and then deliver them to a spacecraft.

Assuming cost is not an issue, how realistic would it be for this mission to take place within, say, the next 50 years? Which of the obstacles I outlined is the most difficult for modern human civilization to overcome? Are there other problems I haven't thought of that would make this idea impossible?