Behavior of test particles in the plasma sheath upon local bias and plasma switching

TL;DR

This study investigates how test particles behave in plasma sheaths when local bias voltages are applied or switched, revealing how sheath conditions influence particle charge and position.

Contribution

It provides experimental insights into particle dynamics and charge variations in plasma sheaths under bias switching and discharge afterglow conditions.

Findings

Particle charge and position depend on sheath structure and bias conditions.

Switching bias causes damped oscillations or accelerated fall of particles.

Particle behavior persists in plasma afterglow with sustained bias.

Abstract

Equilibrating gravitation by electric forces, microparticles can be confined in the plasma sheath above suitably biased local electrodes.Their position depends on the detailed structure of the plasma sheath and on the charge that the particles acquire in the surrounding plasma, that is by the electron and ion currents towards it. Bias switching experiments reveal how the charge and equilibrium position of the microparticle change upon altered sheath conditions. We observe similar particle behaviors also in the afterglow of the discharge for a persisting bias voltage on the electrode: damped oscillation into a new equilibrium or (accelerated) fall according to the bias.