The bomb or power-plant starts off without any explosives, simply bringing up the pressure by focused solar heating melting salt.-- pashute, Jul 20 2020 Ivy Mike https://en.wikipedia.org/wiki/Ivy_MikeLoud noise, very far away. [8th of 7, Jul 20 2020] You're never going to build a field-deployable weapon that way; you'll end up with something bigger than the Ivy Mike gadget <link>.
As to initiating a fusion reaction for power generation, it will need a fairly big array to collect enough energy to do the job; focusing will B an issue.
Might be better just harvesting the energy and feeding it into a conventional fusion reactor to heat the plasma to burn point.-- 8th of 7, Jul 20 2020 Focusing is not engineered placement, more chucking in finer local direction.-- wjt, Jul 24 2020 random, halfbakery