Besides the Gun-Type Device, there was the Implosion-Type Device.
What was implosion?
Ordinary explosions erupted from the inside out. Implosion was different—it compressed through a reverse explosion, from the outside in.
An Implosion-Type Device used the energy of explosives to rapidly squeeze several subcritical pieces of Nuclear Weapon Raw Material into a very small volume, bringing them into a Supercritical State.
It was like having over a thousand students standing in a circle around a field all push toward the center at the same time, ultimately cramming together in an area of only a few square meters. Their density would then be astonishing. With Nuclear Weapon Raw Material, that meant the density of atoms reaching a terrifying level, far exceeding Critical Mass.
This resulted in a higher utilization rate for Nuclear Weapon Raw Material and greater power, but it also increased the technical difficulty.
The most crucial issue was how to make the many pieces of Nuclear Weapon Raw Material compress simultaneously. To use the earlier example, it was how to make a thousand people on a field all reach the center and squeeze together at the same time.
Nuclear Weapon Raw Material was driven by detonation waves from explosions, but the inward-propagating detonation waves of ordinary explosives were inherently asynchronous, because they spread outward in a circle from a single point.
As a result, the Nuclear Weapon Raw Material being pushed would develop differences in curvature.
Such differences were insignificant in other explosions, but in a nuclear explosion timed down to fractions of a second, they were fatal.
To ensure the implosion effect, the explosion had to be improved so that the detonation waves did not propagate in a circular pattern, but in planar ones. Only when numerous planes connected together and pressed inward simultaneously could they form an