The cavitation bubble is the engineer’s best friend. The more that I get to know it, the more I like it. At its very heart, it is an energy storage device; like a spring that transforms kinetic energy into potential energy.
For acoustic cavitation, the cavitation bubble saves sound energy like a battery up until the liquid that supports the bubble is no longer capable of holding any more.
The bubble starts down hill picking up speed and efficiently concentrates all that stored kinetic energy into of small volume only a scant one half of a nanometer in diameter.
It has been calculated that a cavitation bubble can concentrate energy by at least a factor of 12 orders of magnitude. That is the low end estimate, it could be much more!
But for ultrasonic drive cavitation, the fluid is the limiting factor in how much energy that the bubble can concentrate.
In hydrodynamic cavitation however, there is no limit. A bubble produced with a laser or a spark will grow large enough in diameter to store the incoming energy. If the body of fluid that supports the bubble is large enough, the bubble will grow very large indeed. Because the time of the reaction is so short, energy has no time to leak out of the bubble.
All the energy, no matter if it is heat, or light, or x-rays, or gamma rays, or super heated plasma, or relativistic electrons, or subatomic particles, or magnetism, or static charge, all will be absorbed in the bubble wall as it pushes itself ever outward as it struggles to balance all the various forces and stores them for the collapse that will inevitably come. After the impinging onslaught of incoming radiation stops, the bubble will cease to grow, the bubble wall with all its wild undulations complete will then stabilize, and form itself into a perfect sphere, briefly pause, then begin its fall.
Like a bolder falling down a mountain, the bubble wall will pick up speed. The collapsing bubble wall will first reach the speed of sound of its supporting medium and then it will go beyond. It will become supersonic, then hypersonic. A hypersonic shock wave will develop before the wall and clear the way. All the debris and detritus of its creation will now be pushed forward ever faster as it compresses the matter, now plasma ever smaller and denser in a shrinking sphere of compression. Behind the wall a vacuum forms sucking the wall with even greater force than before.
The collapse builds on itself in and exponential acceleration compressing as it goes, the plasma ever denser until the first signs of resistance forms. Slow at first but growing fast. Atoms in the plasma grow ever hotter and denser until they are so close together but still bumping around wildly against each other in maelstrom confusion as their temperature escalates.
Now powerless against all that unimaginable heat and stripped bear of their electrons, the atoms are forced to merge; the forces in the nuclei can no longer keep them apart. They merge together from a pool of their constituent parts. A quark soup is formed. This is when strange things begin to happen where no one can predict what results.
Yes, this is a tale that could very well happen. If the Z-pinch delivers its 350 terawatt lighting bolt into the center of a large sphere of molten salt, the mother of all cavitation bubbles will form.
When all that energy is instantaneously stored with ultra high efficiency then transformed by a perfectly formed cavitation bubble into a hypersonic collapse with a power multiplication factor of 12 orders of magnitude, things will happen, things will definitely happen.
Concentrating all that power into a sub nanometer size region of space will cause varied strange and wondrous nuclear reactions to unfold.
Like the end of any good mystery story, I am curious and excited to see how all these strange and wondrous goings on work out; aren’t you?
The old Zenith slogan: The quality goes in before the name goes on.