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Electric Propulsion Magnets Ready for Space Tests
(spectrum.ieee.org)
This is a most excellent place for technology news and articles.
They are also useful for maintaining orbits (like the ISS), and could potentially be useful in long duration missions such as interplanetary transfers. If it takes months to get to Mars anyway, low thrust won't matter if it means you get more total delta-v, and able to reduce the travel duration anyway, but of course this depends on the specifics