To be clear. This is NOT fusion. It uses some of the same tools that were developed in the, so far unsuccessful, fusion research. It's microwaves. Just the same as you microwave oven except much shorter wavelengths and a LOT more power. Megawatts of power. Using wave guides the millimeter waves from the thing that generates the microwaves is projected in the direction needed, and much like a laser, it burns a hole. A very deep hole.