u/DefinitelyNotMeee

While organizing some of my many bookmarks, I found a link to https://atomicphotographers.com/ website, where in the section dedicated to Harold Edgerton, you can see some of the famous photos captured by Rapatronic cameras.

I remembered the reason why I saved this link was the mystery behind the structures/regions clearly visible in the photos, so I went to The Effects of Nuclear Weapons to look for the answers. Unfortunately, I haven't been able to find a satisfactory explanation of this phenomenon. My other go-to source of all nuclear knowledge, the nuclearweaponarchive.org website, also didn't have the answers I was looking for.
I also searched 'fireball' in the sub and read through many of the posts. I admit not all of them, so I may have missed the answer.

My assumption is that these regions are not really 'voids', but areas of gases at different temperatures/pressures, and are directly linked to the design, components, and internal structure of the corresponding device.

So my question is: what am I seeing in these pictures? What are those blobs and voids?

Note: I'm not talking about the 'rope trick', that's sufficiently explained in the source I have available

Image 1: Mohawk (360 kt), Operation Redwing
Image 2: Priscilla (37 kt), Operation Plumbbob
Image 3: How (14 kt), Operation Tumbler-Snapper
Image 4: Boltzmann (12 kt), Operation Plumbbob
Image 5: ??(??), Operation Tumbler-Snapper