Particle trapping study in multiple-focus acoustic field

Currently various practical applications recommend the simultaneous trapping of many particles rather than one particle only. Although the multiple-focus acoustic field created by 50MHz phased array transducer has been proposed in a previous paper, the ultrasonic attenuation in the particles and acoustic streaming effect have not been taken into consideration. These influences are very crucial to evaluate whether radiation force is big enough to do multiple-trapping. In this paper, both ultrasonic attenuation in the particles and acoustic streaming effect are evaluated and compared with radiation force. Besides, scattering force component and gradient force component at various positions are also evaluated to analyze their relative contribution to the effect of the multiple trapping acoustical tweezers. The results demonstrate that the acoustic tweezers of this model have the ability to produce a set of trapping points that can manipulate multiple particles to desired positions simultaneously, which proves the feasibility of multiple trapping with the consideration of ultrasonic attenuation and acoustic steaming.