The tractor behavior of a zero-order Bessel acoustic beam acting on a fluid sphere, and
emanating from a finite circular aperture (as opposed to waves of infinite extent) is
demonstrated theoretically. Conditions for an attractive force acting in opposite direction
of the radiating waves, determined by the choice of the beam’s half-cone angle, the size of
the radiator, and its distance from a fluid sphere, are established and discussed. Numerical
predictions for the radiation force function, which is the radiation force per unit energy
density and cross-sectional surface, are provided using a partial-wave expansion method
stemming from the acoustic scattering. The results suggest a simple and reliable analysis
for the design of Bessel beam acoustical tweezers and tractor beam devices