3 ms·

Why would any experimenters optimize for Q total if Q plasma is a prerequisite to get anywhere?

• phkahler 5y ago
  The problem is press/marketing. When you read about this stuff 1.0 is claimed to be break-even, the threshold where fusion start to become practical. So in one piece of writing they will talk about this important number and (deliberately) conflate it with fusion being practical. Yes, getting Q plasma above 1 is necessary, but it's about an order of magnitude too low in reality. Sure everyone in the field know that. Her criticism is thats not how its presented to the outside world.
• MobiusHorizons 5y ago
  The concern is that experimenters are wasting time on experiments with promising looking Q plasma but with orders of magnitude smaller Q total (eg pulsed laser systems) It’s important not to forget the big picture. Otherwise you end up optimizing one piece of the system, and causing another piece of the system to work less well in a way the degrees overall system performance.
• ggrrhh_ta 5y ago
  Well, because it makes no sense to try to increase Q plasma; to what end? As pointed by others, you can increase Q plasma at the expense of Q total, thus precisely optimizing for the wrong objective (fusion can be produced and studied without looking at Q plasma or Q total; although reporting Q plasma along with the time that the reaction was sustained is helpful). I give you an analogy: let's make the most power-efficient floating point unit; but let's focus on Q_float, instead of Q_total; at the end we would end with a simple very wide adder; if we want to multiply two numbers, the system will convert them to their logarithms, add them, and then use exponentiation. Yes, the floating point unit consumed very little power Q_float was great. Well, I guess you get the point.