Damping of a Micro-electromechanical Resonator in the Presence of Quantum Turbulence Generated by a Quartz Tuning Fork

micro-electromechanical resonator, consisting of a 125 × 125 m^2 center plate suspended 2 m above a substrate, was immersed in ^4 He along with a quartz tuning fork. The tuning fork was placed 5 mm above the resonator and was used to generate turbulence. The damping of the resonator was investigated in the presence of turbulence generated by the tuning fork. We observe a velocity, v_c ≃ 5 mm s^-1 , above which the damping on the resonator is drastically reduced for all tuning fork velocities studied. We attribute this change in damping to the shedding and capture of vortices.