Sonoluminescence: Coupling to an applied magnetic field

We investigate several means of coupling between a sonoluminescing bubble and an applied magnetic field. Recent experiments show a strong quadratic dependence between the forcing pressures required for stable sonoluminescence and magnetic field amplitude. However, all coupling mechanisms calculated here for comparable magnetic fields involve energies no more than one percent the mechanical energy of bubble collapse. We conclude that the applied field must influence the system though its effect on some parameter which the bubble motion depends upon very sensitively. A few such mechanisms are suggested. (C) 1998 Elsevier Science B.V. All rights reserved.