Single-bubble sonoluminescence in water during transitions from hypergravity to low gravity on NASA’s KC-135 aircraft and laser-beam extinction methods for studying bubble dynamics

Abstract

The sound field which drives SBSL also provides the radiation force which counteracts the average buoyancy of the bubble. One consequence is that the location of the bubble should be altered by the effective acceleration of gravity ge. Variations in ge may alter the physical processes giving rise to luminescence. This group’s previous experiments have confirmed that SBSL is not automatically quenched in the reduced and enhanced ge conditions in an aircraft undergoing parabolic flight trajectories [D. B. Thiessen et al., in Proc. of the 4th Microgravity Fluid Phys. Conf. (NASA, 1998), pp. 379–383]. The new experiments were carried out with the SBSL chamber in contact with a constant-pressure gas-filled chamber. During intervals of negligible drift in the SBSL intensity, there can be a rapid intensity rise (with a relaxation time of about 5 s) of about 4% as ge is decreased from 1.8 to near 0 g, but the increase is not seen in all data sets. In related work, diagnostics based on monitoring laser-beam extinction with a photocell [J. S. Stroud and P. L. Marston, J. Acoust. Soc. Am. 94, 2788–2792 (1993)] is applied to SBSL bubbles in the laboratory. [Work supported by NASA.]