Yes - exactly this. A very large RTG or even fission powered electromagnet parked at L1.
I would see this sci fi movie!
It wouldn't be a problem for a species with an active space economy to keep a few satellites at L1. Should the species no longer have active space travel then eventually the planet would be screwed though, but how long is "eventually", and how long would the satellite have to be in place before the goal is met.
As a species we struggle do 5 years projects, let alone 500 or 5000 year projects.