40 years ago when I was a kid 'they' were getting to the point of having energy neutral reactions in toroid containers as I recal.
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If you knew how the fusion works on the Sun, you'd know that to make fusion on Earth you need to supply the energy to start the process.
- snip - stuff that everyone who matters already understands (as either correct or incorrect.)
Ya, that's how almost all reactions work geenyus. So what?
Energy from fusion < (Energy required to produce hydrogen + Energy required to start fusion)
Go back to injuneering school please.
Anyway, once you are disabused of your rather comical mis-understandings of physics, chemistry, thermodynamics, and basic system analytics:
PETN needs a particular form of energy from a blasting cap to detonate it. Again, so what?
Edit: Of course the fusion reaction underway in our sun is not net positive energy. The reaction only sustains because of energy from God which 'produces hydrogen'. Just ask BADecker as our resident authority on all things God.
More seriously, the high energy consumption of tokamak reactors was, as I recall, associated with maintianing the magnetic field needed to contain the plasma. Early experiments required an input of energy to achieve this, and they also did not focus on extraction of energy. That would come later.
Note that the early diesel engines did 'work', but they did not generate enough power to overcome their own internal friction. Once the principle was demonstrated they rapidly developed into very useful and serviceable devices indeed.