Abstract: Influence of parameters such as attenuation coefficient,velocity of sound,and temperature of medium on focusing sound field generated by a self-focused concave spherical radiator has been studied through numerical simulation with Ray-leigh integral.The results show that characteristics of focal regions are different for various mediums.If the attenuation coefficient increases,the focus moves toward the sound source and the focal region shortens.If the velocity of sound increases,the focal distance will decrease and the pressure and the size of the focal region will increase.Influence of temperature on focusing effect is not obvious as the temperature changes a little.

Key words: high intensity focused ultrasound, sound focal region, attenuation coefficient, temperature