  Experiments on generation of 1, 2, 4, and 6 sonoluminescent bubbles in water
with an external ultrasound source in an acoustic sphere resonator with glass
walls have been carried out. Theoretical examination has shown that the
observed excitation frequencies could be described with a good accuracy taking
into account that the velocities and pressures of the contacting media on the
external and internal resonator surfaces are equal. The necessity of accounting
for oscillations with non--zero self--values of angular momentum operator has
been shown when describing the features of localization of several bubbles. To
explain a strangely small distance between the bubbles in the case of
two--bubble sonoluminescence the following possible explanations have been
proposed: a) mechanism of space splitting of a mode with a singular angular
momentum and b) mechanism of secondary excitation when one of the bubbles is
trapped into the acoustic trap created by high--frequency vibrations arising
simultaneously when the other bubble sonoluminescence occurs.
