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Dynamic Entropy of Two-Dimensional Active Brownian Systems in Colloidal Plasmas
Xeniya G Koss1,2, Evgenii A Kononov1,2, Irina I Lisina1
1Joint Institute for High Temperatures, Russian Academy of Sciences, 125412 Moscow, Russia.
Molecules (Basel, Switzerland)
|March 10, 2022
Summary
Active Brownian micrograins in plasma exhibit altered motion with increased laser power. Janus particles shift from chaotic to spiral paths, while fully covered grains show a transition from ordered to disordered structures.
Area of Science:
- Plasma physics
- Soft matter physics
- Statistical mechanics
Background:
- Active Brownian particles (ABPs) are model systems for self-driven entities.
- Understanding microparticle dynamics in radiofrequency (RF) plasmas is crucial for materials science and industrial applications.
- Previous studies have explored ABP behavior, but detailed analysis in complex plasma environments is ongoing.
Purpose of the Study:
- To investigate the influence of varying laser power (and thus kinetic temperature) on the motion of active Brownian micrograins in RF discharge plasmas.
- To differentiate the dynamic behaviors of fully metal-covered plastic grains versus Janus particles under these conditions.
- To analyze structural changes and phase transitions within the microparticle system.
Main Methods:
- Experimental tracking of individual microparticle trajectories in RF plasma.
- Calculation of pair correlation functions to characterize particle arrangements.
- Analysis of Mean First Passage Time (MFPT) dynamic entropy, fractal dimension, and mean localization area as functions of kinetic temperature.
Main Results:
- Increased laser power leads to significant changes in micrograin motion.
- Janus particles transition from chaotic to spiral trajectories.
- Fully covered particles exhibit a dynamical phase transition from ordered to less ordered structures.
Conclusions:
- The kinetic temperature, controlled by laser power, dictates the collective behavior and structural organization of active Brownian micrograins in RF plasmas.
- Different microparticle designs (Janus vs. fully covered) display distinct responses to changing energy input.
- The study reveals a tunable transition in microparticle system dynamics and structure.
Keywords:
Brownian motionMFPT dynamic entropyactive Brownian particlescolloidal plasmasfractal dimensionMore Related Videos
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