t_c = 0.9146·R₀√(ρ/p∞) — Rayleigh 1917. Bubble wall velocity at collapse can exceed 1000 m/s, creating microsecond hot spots (~10,000 K, 1000 atm)
Sonoluminescence: adiabatic compression heats gas to plasma temperatures — light flashes last ~100 ps, implying temperatures comparable to the sun's surface
Transient cavitation (collapse in one cycle) vs. stable cavitation (oscillate many cycles). The Bjerknes force attracts bubbles toward pressure antinodes