Dynamics of the vortex-particle complexes bound to the free surface of superfluid helium

TL;DR

This study investigates the complex two-dimensional behavior of charged nanoparticles on superfluid helium's surface, revealing distinct vortex structures and particle trajectories through combined experimental and theoretical analysis.

Contribution

It introduces a detailed analysis of vortex-particle interactions at the superfluid helium surface, identifying new vortex configurations and particle dynamics.

Findings

Identification of two particle trajectory types

Observation of vertical and half-ring vortices

Correlation between vortex structures and particle motion

Abstract

We present an experimental and theoretical study of the 2D dynamics of electrically charged nanoparticles trapped under a free surface of superfluid helium in a static vertical electric field. We focus on the dynamics of particles driven by the interaction with quantized vortices terminating at the free surface. We identify two types of particle trajectories and the associated vortex structures: vertical linear vortices pinned at the bottom of the container and half-ring vortices travelling along the free surface of the liquid.