Rotating gradient measurement of bubble dynamics

A rotating gradient method is used to measure the steady-state bubble response under constant drive conditions. The rotating gradient drive is produced with alternating currents in a single-level conductor configuration. In response the bubble propagates at constant speed along a magnetooptically observed circular trajectory. A measurement of the trajectory diameter and the bubble's azimuthal position relative to drive with clockwise and counterclockwise gradient rotation characterizes the steady-state response and the effective bubble mass.