# New approach to measurement of the three dimensional crystallization front propagation velocity in strongly coupled complex plasma

## TL;DR

This paper introduces a new algorithm for measuring the three-dimensional crystallization front velocity in complex plasma, providing a reliable kinetic characteristic of plasma crystallization on the ISS.

## Contribution

The paper presents the 'axis' algorithm for identifying solidlike particles and accurately measuring front velocity in complex plasma crystallization.

## Key findings

- Front velocity is approximately 60-80 microns per second.
- Velocity is nearly independent of time and propagation direction.
- Algorithm effectively isolates crystal domains and their surfaces.

## Abstract

The PK-3 Plus laboratory onboard the International Space Station is used to form complex plasma with a liquidlike particle subsystem in metastable state and to observe the propagation of crystallization fronts corresponding to the surfaces of crystal domains. We propose the "axis" algorithm of solidlike particles identification, which makes it possible to isolate different domains and their surfaces as well. Determination of the three-dimensional front velocity is based on its definition implying that there exists a small area of the domain surface propagating along some line perpendicularly to it. The velocity measured in this way is an important characteristic of the plasma crystallization kinetics. It proves to be almost independent of time and the direction of front propagation and amounts to ca. 60--80 micron per second.