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> achieving the actual energy break even instead of laser energy break even. Can someone elaborate on why laser energy break even was even a big deal? Why does

> achieving the actual energy break even instead of laser energy break even. Can someone elaborate on why laser energy break even was even a big deal? Why does that matter? Doesn't only total net energy matter?

throwup238 3y ago
The former is a milestone for the latter. In order to demonstrate that net energy for the process is even possible, they have to show that the ignition can be breakeven. By analogy they have to show that combustion is possible before spending even more money on building a giant gas fired power plant. It's a small milestone, but it's a very important stepping stone if there's going to be any future for it. Getting it to the commercial power plant stage is a much more holistic problem that will probably take 10x more investment which no one wants to spend sight unseen.
cstoner 3y ago
While it's true that total net energy is what ultimately matters, the article points out that 99% of the energy that goes towards the lasers is wasted. So it seems like a logical next milestone.
dotnet00 3y ago
Prior to this, ignition had only been achieved in hydrogen bombs. Basically, they confirmed that it is possible to have a controlled fusion reaction where the reaction puts out more energy than was put into the reaction, a prerequisite step to being able to put out more energy than was put into the entire machine. Everyone assumed that controlled ignition was possible, but it's still meaningful to be able to prove it experimentally, particularly since now they can probe the limits and understand how different factors affect the result.
- okdood64 3y ago
  Is a big loss here laser efficiency and cooling issues?
  - dotnet00 3y ago
    I attended a presentation by the NIF guys earlier this year at a conference, where IIRC one of the bigger challenges was the optics. Due to the amount of energy being put through them (particularly since it was pulsed), any imperfections would be amplified, quickly rendering the component unusable. They ended up developing an entire automated system for fixing these using an approach I can't recall. So I guess the losses in terms of reaching break even (which this facility is not specifically aiming for, its main purpose is to ensure our hydrogen bombs still work) are the electricity-to-laser efficiency (IIRC these lasers are pretty old now and less efficient than modern lasers), making optics which can better tolerate the energy, getting the timing right so that the pellet is compressed equally (any imbalances manifest as reduced efficiency) and making better pellets (since of course, this is also an energy intensive process at the moment).
  - itishappy 3y ago
    Yup. Also energy recapture. (I suppose you could argue that's included in "cooling issues.")

throwup238 3y ago

The former is a milestone for the latter. In order to demonstrate that net energy for the process is even possible, they have to show that the ignition can be breakeven. By analogy they have to show that combustion is possible before spending even more money on building a giant gas fired power plant. It's a small milestone, but it's a very important stepping stone if there's going to be any future for it. Getting it to the commercial power plant stage is a much more holistic problem that will probably take 10x more investment which no one wants to spend sight unseen.

cstoner 3y ago

While it's true that total net energy is what ultimately matters, the article points out that 99% of the energy that goes towards the lasers is wasted. So it seems like a logical next milestone.

dotnet00 3y ago

Prior to this, ignition had only been achieved in hydrogen bombs. Basically, they confirmed that it is possible to have a controlled fusion reaction where the reaction puts out more energy than was put into the reaction, a prerequisite step to being able to put out more energy than was put into the entire machine. Everyone assumed that controlled ignition was possible, but it's still meaningful to be able to prove it experimentally, particularly since now they can probe the limits and understand how different factors affect the result.

okdood64 3y ago
Is a big loss here laser efficiency and cooling issues?
- dotnet00 3y ago
  I attended a presentation by the NIF guys earlier this year at a conference, where IIRC one of the bigger challenges was the optics. Due to the amount of energy being put through them (particularly since it was pulsed), any imperfections would be amplified, quickly rendering the component unusable. They ended up developing an entire automated system for fixing these using an approach I can't recall. So I guess the losses in terms of reaching break even (which this facility is not specifically aiming for, its main purpose is to ensure our hydrogen bombs still work) are the electricity-to-laser efficiency (IIRC these lasers are pretty old now and less efficient than modern lasers), making optics which can better tolerate the energy, getting the timing right so that the pellet is compressed equally (any imbalances manifest as reduced efficiency) and making better pellets (since of course, this is also an energy intensive process at the moment).
- itishappy 3y ago
  Yup. Also energy recapture. (I suppose you could argue that's included in "cooling issues.")