[Zathras]

Sounds alot like the 2 stage H-bombs of the early 60's.
They also used heated foam to generate X-rays to compress Deuterium. Interesting!

[Poohbah]

That's actually a common misperception.

The foam didn't react appreciably--it was used because it was relatively transparent to X-Rays, but could be cut easily into whatever shape was necessary to support the components and keep them aligned.