I'd like to know what theoretical methods for initiating a fusion detonation without a fission trigger exist, and which would be the most practical in the near future. I'd also like to know how small A fusion bomb might be practical under those circumstances. For instance I think you could probably initiate a fusion detonation if you collide 2 suitable masses into each other at a couple hundred miles per second, but that wouldn't be practical from a weapons standpoint. I'm thinking maybe laser initiated fusion or some kind of explosive magnetic compression or combinations or a host of other things I probably haven't even considered.
I will make this into an answer since the comment format is too constrained.
It is instructive to read the wiki article on the hydrogen bomb. It is evident that to get a bomb by fusion one needs the high temperatures generated by the fission core plus the compression that feeds the plasma of hydrogen, for fusion to happen. These needs cannot be satisfied by lasers or magnetic fields.
A bomb cannot be made out of a setup that is studying and will be used for fusion as an energy source. Pellets and lasers etc work on too small a volume to sustain a nuclear explosion if the density of the gas is not dramatically increased. Take the ITER design, it cannot be made into a bomb. Nor the pellets and laser designs., the volumes are small and fusion can be sustained by continuous feeding, but no high enough pressure in a large scale can be achieved with these methods; so no explosions.
So, fortunately, there is no known method now that a fusion bomb can be made without the extraordinarily complicated A bomb in its core.