Feed in mix of deuterium and tritium.
Heat and compress to plasma
Feed mix into the reaction pathway, a strongly confined shaped magnetic tunnel surrounded by an Archimedes screw of high intensity lasers, set in vacuo to avoid contact with physical material.
Generate continuous heating via lasers as the plasma passes along the reaction pathway until fusion finally occurs in the short fusion zone.
Allow hot fused products to expand into expansion chamber
Pass through suitable heat exchanger to make steam/molted sodium or whatever takes your fancy.
Use some of the generated energy to power process. Very possibly some of the products might be useful hot feed-stock for lasing medium.
The lasers are in a continuous spiral (inspired by the Archimedes screw), so that the plasma heats up as it passes through them until it starts to fuse. You still need serious magnetic confinement to keep the plasma confined while it is heated, but there is nothing physical in the path to touch, just magnetic fields and lots of laser beam.
I can’t see any immediate reasons why it couldn’t work, and it offers some definite advantages over a torus approach or exploding pellets. The magnetic fields needed are high to keep the plasma confined, just as they are in other fusion systems and also as usual, putting the reactor part in vacuo prevents contamination by other gases or material from reaction chamber walls. It is really just a simpler rearrangement of current toroid approaches. The main difference is the Archimedes screw laser arrangement and the magnetic field design. These would determine the quantity of reactants present and their rate of progress through the tunnel as the lasers heat them up.