Steam-powered piston system sparks nuclear fusion plasma in Canada

They've tested that their plasma injectors work well when combined with their actual test chamber.

They haven't attempted compressing the plasma in the test chamber yet (their press releases indicate that they've tested the mechanical compression earlier).

The machine under test is a prototype. Instead of a liquid lithium liner being compressed by pistons, they're using a solid lithium liner that's being compressed magnetically (z-pinch basically I think). This means that this prototype has basically no power generation potential.

What this prototype does derisk is I guess.. exactly the plasma injection process, and probably a bunch of aspects of their compression/fusion modelling. If this round of prototyping goes well (up to and including fusion and fusion breakeven), then they have to figure out their entire liquid lithium recirculation and compression systems, and then their energy capture systems.

I understand that the plasma injection process is non-trivial. They're basically trying to inject plasma smoke rings. Except these are smoke rings that magnetically self interact with themselves.

The superconducting magnets, lasers, etc. mentioned are as used in tokamak (doughnut shaped) reactors that most labs use. This is a completely different design, that seems intended to be quicker/cheaper/easier to roll out if they can get it working; they've achieved some progress in that regard, but still not fusion even, just a significant step towards it. (Fusion has been achieved in tokamaks, just not for very long and not net energy producing.)

For this prototype, I understood that they're using solid lithium liners. They have a casting die to make the lithium wall, so this is strictly a single shot + long reset type of thing.

I believe their proposal for an operational system is that they use a liquid lithium wall which they keep spun up for form a liner. This liquid lithium is also supposed to be their primary working fluid, so it'll be kept liquefied and continuously circulating.