Research


This page outlines some of the research topics that I am interested in.

Plasma Physics

Plasma physics is the branch of physics that studies ionized gases.  The pictures above show many regions in the universe where plasmas are important: (from left to right) the galaxy Cenaurus A (with its radio jets); the sun, aurora, and tokamak machines designed to produce energy from nuclear fusion; and basic laboratory experiments.  Some of the specific areas within plasma physics that I am interested in are given below.

Wave transport.  There are aspects of fundamental plasma physics that involve kinetic theory and wave-particle interactions that are still open questions.  For example, what are the mechanisms that force regions, which are out of equilibrium with their surroundings, into equilibrium?  Do the many wave modes that exist in plasmas contribute to this process?  Areas where this might be important are tokamaks, auroras, and pulsars.  I am investigating the role that waves play in this process.  I am using computer simulations to see how a hot plasma region, for example, cools when surrounded by a cooler plasma.  Of course, the usual mechanisms of conduction and convection occur, but the mechanism of "radiation" can play an enhanced role due to the large number of normal modes that exist in plasmas.

Diagnostics of Inertial Fusion Plasmas.  One of the important thrusts for society as a whole is to develop forms of energy that are alternatives to fossil fuels.  One of these currently being hotly investigated in fusion energy.  And one method of producing fusion is through laser-plasma interactions, also known as inertial confinement fusion.  The key to producing commercial power is understanding the physics of these plasmas, and the key to understanding the physics is good diagnostics - that is, what is happening in these plasmas.  One diagnostic tool is the spectral analysis of Stark-broadened emission lines.  The shapes of these lines, however, is affected by the surrounding plasma, in particular by the dynamics of the ions.  I am using computer simulations to investigate exactly how the plasma affects the line shapes.
 
 

Space Physics

Space physics is the application of plasma physics to the plasmas in the solar system.  These pictures show the Sun and the Earth (not to scale!) and their interaction through the Sun's corona and solar wind, and the Earth's aurora.

Plasmasphere.  One of my current research interests in space physics is modeling the plasmasphere. The plasmasphere is a torus-shaped region of space between about 3,000 km and 40,000 km altitude, at low latitudes.  It is a part of the Earth's magnetosphere.  The plasma in this region affects ground-to-satellite communications and also navigation.  I am currently modeling the structure and dynamics of the plasma density in the plasmasphere.

Auroral Ionosphere.  This region of space near the Earth is a dynamic region, where lots of basic plasma physics issues can be studied.  One current area of study is the generation mechanism of all the waves that are observed.  One possible mechanism is the velocity shear that is ubiquitously observed.  Regions of plasma flow (relative to neighboring regions) have free energy with which to excite many different wave modes.  I am currently looking at the theory of such plasmas to determine their response to such flows, and what waves might be the most likely to be observed.


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Last Modified: 9 October 2001