BTW I doubt the energy yield of an imploding sphere is anywhere close to a nuclear device, but implosion is a very rapid process, so its power output is indeed very high. Examples:
- Pistol shrimps create cavities whose collapse emits light. https://arstechnica.com/science/2022/07/pistol-shrimp-sport-...
- A Super-Kamiokande PMT implosion triggers a chain reaction. http://hyperphysics.phy-astr.gsu.edu/hbase/Particles/kamio.h...
- Downed WWII aircraft dropped hollow spheres into the ocean whose implosion, heard thousands of miles away, signalled their position https://shaunmccarthy.wordpress.com/2008/07/13/ww2-secrets-t... https://acousticstoday.org/wp-content/uploads/2021/03/Underw...
Also, imploding spheres have been used as a proxy for nuclear detonations in calibration experiments for sound-based nuclear blast detection: https://inis.iaea.org/collection/NCLCollectionStore/_Public/...