Axial radiation force of a Bessel beam on a sphere, direction reversal of the force, and solid sphere examples

Abstract

The exact solution for the axial radiation force on an isotropic sphere centered on an acoustic Bessel beam in an inviscid fluid was recently given [P. L. Marston, J. Acoust. Soc. Am. 120, 3518–3524 (2006)]. Following a review of the physical relevance of such radiation force calculations for acoustic plane waves, the Bessel beam radiation force derivation and results will be summarized. In the ordinary case, the direction of the axial force is parallel to the propagation direction of the beam. Among the predictions given in the publication is the possibility of an axial radiation force on certain fluid spheres for which the force is directed opposite to the propagation direction. In a recent extension of the published work, conditions have been identified for such a force reversal on solid spheres and elastic shells. These calculations give insight into situations where the radiation force of acoustic beams may be used to pull (instead of push) spherical objects. [Research supported in part by NASA.]