I have not been able to locate this information. To trigger the fusion inside a weapon. That is hydrogen atoms fusing to become helium as happens in the sun and thus releasing huge amounts of energy, you have to have temperatures and pressure similar to that in the sun. And the only way you can produce that is by detonating a small fission explosive in close proximately to isotopes of hydrogen. Virtually all of these "fission triggers" are plutonium type "implosion" devices from what I've read. Where the fission explosion is produced by crushing concentric spheres of plutonium together by powerful conventional explosives. So, how high a yield in kilotons are these "fission triggers"?