Doctor of Philosophy
Dusty plasmas represent four-component partially ionized gases consisting of ions, electrons, neutral gas molecules, and dust particles. The dust comprises solid particulate matter typically submicron or several microns in size, and when dispersed in plasmas, they typically acquire a high negative charge due to the electrons having much higher mobility than the positive ions. As a result of their charge, they experience strong electric forces, respond to external fields, and perturb the plasma conditions, and therefore, they cannot be treated in isolation from other particles and from the plasma itself. Depending on their strength of interaction and the plasma conditions, the particles can self-organize into gas, liquid, or crystal-like states and exhibit collective behavior giving rise to a rich variety of interesting phenomena widely observed in space, laboratories, and industrial plasma processing devices. The intrinsic complexity and multiscale dynamics of dusty plasmas make them challenging to theorize about and suitable for computational studies. This dissertation focuses on modeling dust-level processes (Chapters 3,4, and 5) including particle charging and ion-drag forces, and dust-phase level thermodynamics (Chapter 6) using Langevin Dynamics (LD) simulations. At the dust level, the interactions between a single negatively charged dust particle and a collection of ions are analyzed to quantify the particle-ion collision rate coefficient and ion-drag forces. At the dust-phase level, interactions between a collection of negatively charged dust particles are analyzed to compute thermodynamic state variables such as pressure, internal energy, and kinetic energy. Predictions made by the model are validated against measured values from the Plasma Kristall-4 (PK-4) microgravity experiments that were carried out in the International Space Station. For the dust-phase level analysis, LD simulation procedure, validation methodology, preliminary validation results using data from ground-based dusty plasma experiments, and scope for improvement and future work are discussed.
Dissertation or thesis originally submitted to ProQuest.
Suresh, Vikram, "Investigation of particle-level and particle phase-level processes and interactions in dusty plasmas using Langevin Dynamics simulations and trajectory analysis methods" (2022). Electronic Theses and Dissertations. 3290.