... this appears to be a 'rapatronic' image from the first micro-seconds of the 'Mike' shot in 1952. The color images were not released to the public until over ayear later. Which accounts for the 1954 date of the magazine.
Roughly speaking the 'fireball' is the place where the real nuclear-atomic bang part is taking place. The rest of the big show: blast, mushroom clouds, fallout etc all being just aftermaths.
I repeat my question of where are the rest of the detail high speed camera shots of the H-bomb tests. This series (start pg 21) seems to be all we have seen (from 62 years ago). There are a number of high quality images from the earlier A-bomb tests in Nevada (all in black and white).
My guess, and the answer to my question, lays in the fact that these are not just vacation snapshots of "what I did on my trip to the South Pacific". The fact is that such photographic documentation was a highly complex and expensive way of gathering scientific data. (A-bombs (purely fission devices) are oh, so old school)! All 'modern' nuclear weapons are variations on the H-bomb concept; available in convenient sizes of small, king-sized and Jumbo!. So the detailed images of the first millionths second of an H-bomb fireball still hold scientific secrets! Or nobody has simply got around to declassifying them yet.