A Curvature-Driven Plasma Mechanism Explains the Blackbody-Like Continuum in Single-Bubble Sonoluminescence

Abstract

Single-bubble sonoluminescence produces picosecond optical flashes from a micron-scale bubble collapsing under acoustic drive. Although the emitting region is sub-wavelength and cannot thermalize, the resulting spectra resemble blackbody continua with apparent high temperatures. Here we show that these continua arise not from temperature but from a curvature-weighted emissivity mechanism associated with the scalar temporal field whose gradient defines local dynamical time. During collapse, rapid interface acceleration excites short-lived curvature pulses in the transverse temporal manifold, and electromagnetic emissivity is exponentially amplified by the instantaneous curvature magnitude. A universal scaling relation emerges naturally. Across four fluids spanning eight orders of magnitude in brightness, published data fall on a single line. The continuum slope, line suppression, drive invariance, and fluid dependence all follow from this geometric mechanism, indicating that sonoluminescence is a curvaturedriven, nonthermal plasma excitation.

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