OK, you are getting past my level of knowledge in physics...(I didn’t stay at a Holiday Inn Express last night!)....but kinetic weapons from orbit look like a more viable (cheaper/actually deployable) option than “energy beams”.
https://www.nextbigfuture.com/2018/11/orbital-kinetic-bombardment-gets-close-to-nuclear-on-damage-and-cost.html
TXnMA