Physics Seminar: Experimental and Molecular Dynamic simulations of the interaction of a dusty plasma system with an energetic electron beam

Dr. Jeremiah D. Williams
Department of Physics
Wittenberg University, Springfield, OH 45504
jwilliams@wittenberg.edu

Abstract

In nature, matter naturally exists in one of four states.  The most common (and least familiar) of these states is a plasma, an ionized gas composed of ions, electrons and neutral particles.  When particulate matter enters a plasma, it becomes charged through interactions with the electrons and ions in the background plasma. Once charged, this third charged species fully interacts with the other plasma components and self-consistently alters the properties of the surrounding plasma.  The resulting system is known as a dusty, or complex, plasma; a non-linear system that is notably more complex than the traditional plasma and supports a wide range of new plasma phenomena including new wave modes and strongly coupled phenomena.

These dusty plasmas are ubiquitous in nature and in laboratory and, in many of these environments, are exposed to energetic electrons. These interactions can lead to a wide range of plasma instabilities and have several industrial interactions. Despite this, the interaction between dusty plasmas and energetic electron beams have not been extensively examined.  Recent experimental studies of the interaction of a narrow, pulsed electron beam (EB) with energies from 10 – 15 keV with dusty plasma have revealed a system rich with physics that arise from the interaction between the charged dust grains and the electron beam.

In this talk, I will present a brief introduction to dusty plasmas and an overview of recent experimental results with supporting molecular dynamics simulations showing the interaction of an electron beam with a dusty plasma system.  This work is supported by National Science Foundation Grant Number PHY-2010122.

Bio:

Jeremiah Williams grew earned a BS in Physics and Mathematics from Dickinson College in 1998 and an MS in Physics from UCLA in 2000.  After completing his masters degree, he was a visiting Instructor at Illinois Wesleyan University for three years before returning to complete his PhD at Auburn University in 2003.  He joined the faculty of Wittenberg University as a member of the Physics Department, where he teaches courses across the physics curriculum, directs the Wittenberg University Plasma Laboratory and is currently the chair of the Physics Department.  His research is currently supported by the National Science Foundation, the Department of Energy and NASA. 

WebEx Meeting link:

https://wright.webex.com/wright/j.php?MTID=m8132ab7a42791df6fa5375ac4fdc498c

Meeting number: 172 516 3608; Password: Pg9JayEqE73