Radiation Mechanism for a Single Bubble Sonoluminescence

Abstract

A mechanism of light emission from a single bubble sonoluminescence (SBSL) was formulated by assuming that the source for the light emission is bremsstrahlung in partially ionized gases. This emission mechanism turns out to be same as the black body radiation with finite absorption, which confirms that the principal mechanism of SBSL is bremsstrahlung with slight black body emission nature. Also the spectrum was measured and the observed results were compared with the calculated ones. Calculated and experimental results yield common spectral behavior in the visible region: the spectral radiance shows power-law dependence on wavelength with an exponent of -2.5. The SBSL spectrum which is characterized by the continuous one with no major peaks has been confirmed experimentally. The bubble dynamics model proposed also takes account the afterpulse characteristics of SBSL.