I doubt that particular magnet but there is a YC startup working on a magnets -> fusion -> space drive thing

https://news.ycombinator.com/item?id=8178450

https://www.nextbigfuture.com/2013/11/john-slough-personally...

For a magnet to be used as propulsion, you'd need something for it to pull or push against.

Finding a likely target seems impossible. The way magnetism drops off with distance means it would only be useful when you were already there (or just starting out).

Also the magnetic field in this case is only lasting a tiny fraction of a second, which would be an issue for propulsion.

In a manner of speaking. There is an idea called a "magnetic sail":

https://www.centauri-dreams.org/2014/08/28/thinking-about-ma...

https://en.wikipedia.org/wiki/Magnetic_sail

http://casa.colorado.edu/~danforth/science/magsail/magsail.h...

My understanding is that it's more useful as a "magnetic parachute", as it lets you brake without using reaction mass, just electrical power. That could let make an interstellar journey with less mass, as you only need reaction mass to accelerate on departure, and not to decelerate on arrival.

If can get to 4 billion tesla I /think/ that's enough to generate electrons from the vacuum of space (see:schwinger magnetic induction) and you could do something akin to magnetohydrodynamics ( see: https://youtu.be/LS3GQk9ETRU ) which would use the magnetic field to accelerate the electrons away from the ship, I could be incorrect here though