What happened to the bubble-like dome that formed after the explosion of a large-yield hydrogen bomb?

It was a dome shape for a short period of time, and then it transformed into a torus-shaped cloud.

"Dome" is actually a hydrogen bomb explosion instant fusion reaction produced by the very high temperature and high pressure heating the air bubble.

"Bubbles" from underwater explosions:

The ring-shaped smoke cloud, termed a condensation cloud.

Hydrogen bomb explosion produced by the mushroom cloud scientific term should be called condensation cloud!

Hydrogen bomb explosion heat instantaneous release, burst the heart of the region will produce tens of millions of degrees or even hundreds of millions of degrees of high temperature, while the explosion in the center of the region to produce billions of atmospheres of pressure, will be evaporated into the soil and the water of the water gas, this high temperature and high pressure under the fireball to the center of the explosion around the intense diffusion of the subsequent periphery of the cooling rate, and the center of the warming and expansion and the rapid rise of two-phase effect, the formation of the tumbling ring-shaped smoke cloud. Smoke cloud in the rise to high altitude, cold liquefaction into tiny droplets, not subject to gravity, floating in the air, the formation of condensation clouds.