Structure and dynamics of shock-induced nanobubble collapse in water.

Shock-induced collapse of nanobubbles in water is investigated with molecular dynamics simulations based on a reactive force field. We observe a focused jet at the onset of bubble shrinkage and a secondary shock wave upon bubble collapse. The jet length scales linearly with the nanobubble radius, as observed in experiments on micron-to-millimeter size bubbles. Shock induces dramatic structural changes, including an ice-VII-like structural motif at a particle velocity of 1  km/s. The incipient ice VII formation and the calculated Hugoniot curve are in good agreement with experimental results.