To my understanding, here they use lasers to create fusion and the 2 megajoules are emitted by the lasers.
Yes.
Hence they need waaay more power than is generated to drive their lasers.
googles
It sounds like the additional power is due to energy exiting the system:
https://en.wikipedia.org/wiki/Fusion_energy_gain_factor
Most fusion reactions release at least some of their energy in a form that cannot be captured within the plasma, so a system at Q = 1 will cool without external heating. With typical fuels, self-heating in fusion reactors is not expected to match the external sources until at least Q ≈ 5. If Q increases past this point, increasing self-heating eventually removes the need for external heating. At this point the reaction becomes self-sustaining, a condition called ignition, and is generally regarded as highly desirable for practical reactor designs. Ignition corresponds to infinite Q.
So it sounds like additional power requirements effectively means getting from their current 1.54 to 5.
That is also why this research is not actually aiming at power geration, but at fusion weapons.
I am confident that that is not the case. The US knows how to do fusion weapons and has for decades – that’s what a thermonuclear bomb is, the second stage. That’s a much simpler problem than fusion power generation. You don’t involve lasers or magnets or other things that you use in fusion power generation if you just want a fusion weapon; you only need to force the material together with a great deal of force for a very brief period of time, and then you’re done.
