It's a reasonable idea, and there's been further work on ignition of fusion reactions with electron beams.[1][2] But not much further work. Ignition with laser beams works, but the equipment required fills a huge building.

If someone figures out how to do this, it becomes possible to make H-bombs without uranium or plutonium. There's a good chance that further results in this area are classified. Much like laser isotope separation, which is known to work and may be a bit too easy.

[1] https://www.researchgate.net/publication/230915062_Initiatio...

[2] https://www.cambridge.org/core/journals/journal-of-plasma-ph...

I'm getting a message "download limit exceeded" when I click the link

This is the project that died...

Thermonuclear Micro-Bomb Rocket Propulsion

https://archive.org/details/DTIC_AD0746027

Note that this is not fission-powered Orion. This is a cleaner He3 - D reaction which produces no neutrons. It's all charged particles, for which magnetic containment is potentially possible.