Acoustic radiation by charged atomic particles in liquids: An analysis

Abstract

A new analysis of the propagation of acoustic pulses produced by local heating of liquids due to ionization by charged particles is presented. It is shown that the wave equations with loss dominate the pulse shape after small distances and that, due to the bipolar $\delta$-function behavior of the individual pulses, a net observed pulse is just the time derivative of the received density of pulses from individual heating centers. Angular distributions, signal-to-noise ratios, detectable volume, and numerical examples are discussed. One important observation is that the effect of attenuation upon this type of radiation is to produce power-law rather than exponential cutoff with distance. For example, in the thermal-noise-limited case the signal-to-noise ratio defined herein only steepens by one-half power in falloff with distance due to attenuation.