Reasonably Warm Fusion

Hi, it's been a while...and I'll kick off with a fusion idea, of sorts.

Background: When a tiny vacuum bubble is induced in a liquid (water), it's collapse is extremely fast, generating enough temperature to make light. It's possible to get hotter than the surface of the Sun. The vacuum bubble can be created by ships propellers, pump impellers or ultrasonic devices. It's good enough to remove metal from propellers and alert U-boats to your presence with the sound.

Fusion from Ultrasonic cavitation (together with some other nuclear "catalyst") has already been investigated, with a brief glimmer of hope, but not replicated.

Now, I am not a physicist, but I think with an engineering hat. This is my logic:

At atomic level- I reason that fusion needs things (probably heavy water) to be both moving very quickly (temperature), and pressed close together (pressure). The "pressed close together" increases the chance of a suitable high energy collision at the right angle, timing, and quantum chance. I would say that the "moving very quickly" (temperature) is the most important.

Now to the idea:

The heavy water is pressurised as much as possible, and then an ultrasonic induced cavity bubble is created. Be aware that 600 bar and 600K is easily possible for steel vessels at 3 ft diameter.. With smaller containers, even higher pressures and temperatures are possible.

The collapse is driven solely by pressure, which is the action of many molecules colliding with each other. To speed the collapse, both pressure and temperature will help. We need the molecules to hit each other fast and often. Fortunately, if the water is pressurised, the temperature can also be increased without vapour forming.

The highest cavity collapse temperatures currently acheived are over 10,000K, starting at ambient temperature and pressure. The collapse is in nano-seconds, and temperature is approximated using the spectrum of light that is emitted. The temperature is much higher when the cavity is as close to spherical as possible. This gives the impression that it is desireable that the collapsing front meets suddenly at the center. Maybe you have seen the wave tank demonstration, where waves are sent to a common centre and the resulting peak reaches the ceiling of the building, or the slow motion captures of things falling into water with a huge spike caused by the closing of the water into the hole?

My proposal is to repeat the experiment, but with as much pressure and temperature as possible. This will collapse the cavity much faster. I further propose that the temperature achieved will be significantly higher, for a shorter period, and the direction of the molecules will be extremely biased to be towards each other.

If it works, the temperature will increase slighly, due to traces of fusion, and this would be a way to have "fusion in a bottle", but not "cold fusion"... shall we call it "reasonably warm fusion"?