Tokamaks are fine, even great, for "research". It is the "development" where they are non-starters. For the last 20+ years it has been pretty obvious that inertial confinement is a way to go to build a working fusion device.
For fusion development where are 2 main factors in play:
1. in the second half of 199x it was decided that fusion plant produced electricity can't be cheaper than the current then $0.04/kwh of coal electricity, thus focus on "research" (especially to support modelling instead of real testing of conventional nukes) not on "development" as energy source
2. non-proliferation. A working inertial confinement device may probably be miniaturized to the military acceptable size of say a large truck/container. Without all the fuss of gigantic multi-year enrichment programs of fissile materials.
Laser driven is an inertial confinement which is well resistable to miniaturization/weaponization due to its complexity and low efficiency [though even that may start to change slowly with semiconductor lasers]. That makes it fine for "research", and there is no need for "development" due to the above mentioned factor #1.
Even 15 years ago it was obvious that somebody need to put DT target inside the wire spool of the Sandia Z-machine discharge target. They probably even did, un-publicly, put it there back then :) They upgraded the machine since then, slowly, and sometimes later (~2010) publicly announced shooting into DT target. Yet it is pretty obvious that they are not in a rush, very very not in a rush... The Z machine schema has much higher efficiency and much lower level tech (i.e. higher theoretical proliferation potential) than femto-lasers.
There is even slower movement, pretty much no movement at all in areas of DPF or fusor-descendant schemas (except a bit for polywell) - the schemas which were beating Tokamaks since the dawn of times, and one can only speculate how things would be if they got even small share of funding that Tokamaks got...
Thanks for your comprehensive comment. It's incredible what level of damage the Cold War has done to nuclear research. Although I'm not 100% convinced it is only bad; we don't want an AK-47 of nuclear bombs until the world is a much more peaceful place than today.
Out of curiosity, what is your background for knowing all this stuff?
For fusion development where are 2 main factors in play:
1. in the second half of 199x it was decided that fusion plant produced electricity can't be cheaper than the current then $0.04/kwh of coal electricity, thus focus on "research" (especially to support modelling instead of real testing of conventional nukes) not on "development" as energy source
2. non-proliferation. A working inertial confinement device may probably be miniaturized to the military acceptable size of say a large truck/container. Without all the fuss of gigantic multi-year enrichment programs of fissile materials.
Laser driven is an inertial confinement which is well resistable to miniaturization/weaponization due to its complexity and low efficiency [though even that may start to change slowly with semiconductor lasers]. That makes it fine for "research", and there is no need for "development" due to the above mentioned factor #1.
Even 15 years ago it was obvious that somebody need to put DT target inside the wire spool of the Sandia Z-machine discharge target. They probably even did, un-publicly, put it there back then :) They upgraded the machine since then, slowly, and sometimes later (~2010) publicly announced shooting into DT target. Yet it is pretty obvious that they are not in a rush, very very not in a rush... The Z machine schema has much higher efficiency and much lower level tech (i.e. higher theoretical proliferation potential) than femto-lasers.
There is even slower movement, pretty much no movement at all in areas of DPF or fusor-descendant schemas (except a bit for polywell) - the schemas which were beating Tokamaks since the dawn of times, and one can only speculate how things would be if they got even small share of funding that Tokamaks got...