title: Theory of the acoustic radiation force exerted on a sphere by standing and quasistanding zero-order Bessel beam tweezers of variable half-cone angles.
abstract: A rigorous theory is developed to predict the radiation force (RF) exerted on a sphere immersed in an ideal fluid by a standing or quasistanding zero-order Bessel beam of different half-cone angles. A standing or a quasistanding acoustic field is the result of counter propagating 2 equal or unequal amplitude zero-order Bessel beams, respectively, along the same axis. Each Bessel beam is characterized by its halfcone angle beta(l);l = 1, 2 of its plane wave components, such that beta(l) = 0 represents a plane wave. Analytical expressions of RF are derived for a homogeneous viscoelastic sphere chosen as an example. RF calculations for a polyethylene sphere immersed in water are performed. Particularly, the half-cone angle dependency on the RF is analyzed for standing and quasistanding waves. Changing the half-cone angle is equivalent to changing the beamwidth. Potential applications include particle manipulation in microfluidic lab-on-chips as well as in reduced gravity environments.
authors.affiliation: Mayo Clinic College of Medicine, Department of Physiology and Biomedical Engineering, Ultrasound Research Laboratory, Rochester, MN, USA. mitri@ieee.org
authors.forename: Farid G
authors.initials: FG
authors.lastname: Mitri
authors.forename: Zine E A
authors.initials: ZE
authors.lastname: Fellah
mesh_terms: D000162:Acoustics; D003198:Computer Simulation; D055119:Elastic Modulus; D008846:Micromanipulation / Q000379:methods*; D008863:Microspheres; D008962:Models, Theoretical; D012542:Scattering, Radiation; D013314:Stress, Mechanical; D014783:Viscosity