

Research Interests 
Theoretical and computational plasma
physics research on fusion and space plasmas, and on coherent radiation
sources. Computing facilities include workstations, 16processor C90 at
Livermore, and 2048 node CM5 at Los Alamos 

URL  www.physics.uci.edu/faculty/chen.html  
Research Abstract 
The main goal of theoretical plasma physics
research is to understand, at a fundamental level, collective
oscillations in essentially collisionfree fully ionized gases
(plasmas). Such plasmas exist both in the space environment, such as the
Earth's Van Allen radiation belt, and in laboratory experiments, such as
the Joint European Torus (JET) for controlled thermonuclear fusion
research. For the past decade or so, my main research interest has been in the area of unstable collective oscillations (instabilities) excited by energetic [O(102) keV ~ O(1) MeV] particles in magnetically confined plasmas. The energetic particles are produced during either geomagnetic storm events or intense laboratory heating and/or future DeuteriumTritium (DT) fusion experiments. These collective instabilities not only could explain the observed electromagnetic wave perturbations but also could lead to, due to their macroscopic temporal and spatial scales, anomalously enhanced transport coefficients, thus affecting the energeticparticle contents and, in the case of alpha particles in the DT experiments, the crucially important fusion ignition conditions. Since the plasmas are typically inhomogeneous and confined by a curved magnetic field, the geometries are complex. The collective instabilities, meanwhile, often evolve into finite amplitudes. We are, thus, dealing with nonlinear wave and particle dynamics in complex systems. Both analytical and computational approaches are necessary in order to provide meaningful insights. Analytical techniques covering a wide range of mathematical physics topics such as complexvariable analysis, WKB approximations, asymptoticmatching analysis, and more, are employed. On the computational physics side, we are developing particlesimulation techniques to describe selfconsistent nonlinear waveparticle interactions. 

Publications  Kinetic Theory of Geomagnetic Pulsations 3. Global Analysis of DriftAlfven Ballooning Modes (with G. Vetoulis), J. Geophys. Res. 101, 15441 (1996).  
GyrokineticMagnetohydrodynamic Hybrid Simulation of the Transition from Toroidal Alfven Eigenmodes to Kinetic Ballooning Modes in Tokamaks (with R. A. Santoro), Phys. Plasmas 3, 2349 (1996).  
Theory of Toroidal Alfven Nodes Excited by Energetic Particles in Tokamaks (with F. Zonca), Phys. Plasmas 3, 323 (1996).  
Theory of Shear Alfven Waves in Toroidal Plasmas (with F. Zonca), Phys. Scripta T60, 81 (1995).  
Resonant Damping of Toroidicity Induced Shear AlfvÚn Eigenmodes in Tokamaks (with F. Zonca), Phys. Rev. Lett. 68, 592 (1992).  
Last updated  04/01/2002 