Experimental Plasma Physics, Lasers, Intellectual Property Law
Fellow, American Physical Society
UC Presidential Faculty Award for Excellence in Undergraduate Research
Daniel G. Aldrich Distinguished University Service Award
Professor McWilliams earned his Ph.D. in 1980 from Princeton University and the B.A. from the University of California, Irvine in 1975. Prior to finishing his Ph.D. he joined the faculty at UCI. His teaching has been recognized with multiple awards for Outstanding Contributions to Undergraduate Education at UCI. He was the inaugural winner of the UC systemwide Presidential Faculty Award for Excellence in Undergraduate Research recognizing his leadership in creating and overseeing undergraduate research opportunities. He was founding director of the Campuswide Honors Program and founder of the Undergraduate Research Opportunities Program.
Plasma physics, the study of matter in the ionized state, is undergoing revolutionary synthesis of theory and experiment. In a general sense, plasma physics is developing most in nonlinear dynamics. Experimentalists seek unprecedented phase-space and turbulence diagnostics, higher spatial and spectral resolution of laboratory and astrophysical measurements, and delineation of particle and energy transport mechanisms. Synthesis of theory and experiment come on a number of fronts, partially responding to empirical advances; large scale computing allows three dimensional, nonlinear models which simulate plasma configurations in laboratory and space. Theoretical, computational, and experimental results allow a coherent picture of plasma physics phenomena to unfold.
Among the most challenging problems for plasma physicists is the understanding of transport properties of plasmas, especially in turbulent regimes. The basic processes of diffusion, for example, have yet to be understood. The transport of particles and energy is an exciting area of plasma research at UCI.
Wave energy transport is understood partially in the linear regime, yet nature is inherently nonlinear in its dynamics. In the laboratories at UCI there is now a sophisticated experimental diagnostic base for addressing transport questions. We have made progress in understanding ion diffusion in quiet or turbulent plasmas, measuring both spatial diffusion and velocity space transport. Measurements have been compared to Fokker-Planck predictions with success.
Experiments study ion diffusion and convection in turbulent plasmas via laser induced fluorescence diagnostics. Wave propagation measurements help to identify the electric field structures responsible for the transport. Experiments with flaring magnetic fields have allowed the study of unusual distribution functions formed by ions interacting with radio frequency waves and the diverging field, phenomena observed momentarily by satellites in the Earth's magnetosphere.
The development of new research tools is important in the plasma laboratory since new tools allow new scientific pursuits. Presently, we are helping develop a new class of diode lasers for laser induced fluorescence diagnostics and telecommunications. This type of work is motivated by the over 20 years of development and utilization of laser diagnostics in the laboratory.
All of this research is done with the close collaboration of graduate and undergraduate students with research physicists and faculty. A primary reason for performing the research at UCI is to train students. Placing students in forefront research efforts is the best training available, allowing considerable one-on-one teaching on topics of interest not only to the student and professor but also to other leading researchers in physics.
Test ion transport in a collisional, field-reversed configuration, T. Roche, R. McWilliams, W.W., Heidbrink, N. Bolte, E.P. Garate, M. Morehouse, M. Slepchenkov, and F. Wessel, Invited Paper, Plasma Sources Science and Technology v.23 (2014) 044001
Measurements of Interactions between Waves and Energetic Ions in Basic Plasma Experiments, W.W. Heidbrink, H. Boehmer, R. McWilliams, A. Preiwisch, Y. Zhang, L. Zhao, S. Zhou, A. Bovet, A. Fasoli, I. Furno, K. Gustafson, P. Ricci, T. Carter, D. Leneman, S.K.P. Tripathi, S. Vincena, Plasma Physics and Controlled Fusion v54, n12, 124007 (2012)
Tomographic Imaging System for Measuring Impurity Line Emission in a Field-Reversed Configuration, T. Roche, N. Bolte, E. Garate, W.W. Heidbrink, R. McWilliams, and F. Wessel, Review of Scientific Instruments 83, 10E503 (2012)
Thermal Plasma and Fast Ion Transport in Electrostatic Turbulence in the Large Plasma Device, S. Zhou, W.W. Heidbrink, H. Boehmer, R. McWilliams, T.A. Carter, S. Vincena, S.K.P. Tripathi, and B. Van Compernolle, Physics of Plasmas 19, 055904 (2012)
Sheared-Flow Induced Confinement Transition in a Linear Magnetized Plasma, S. Zhou, W.W. Heidbrink, H. Boehmer, R. McWilliams, T.A. Carter, S. Vincena, B. Friedman, and D. Schaffner, Physics of Plasmas 19, 012116 (2012)
Dependence of Fast-Ion Transport on the Nature of the Turbulence in the Large Plasma Device, S. Zhou, W.W. Heidbrink, H. Boehmer, R. McWilliams, T.A. Carter, S. Vincena, and S.K.P. Tripathi, Physics of Plasmas 18, 082104 (2011)
Ion Flow Measurements and Plasma Current Analysis in the Irvine Field Reversed Configuration, W.S. Harris, E. Trask, T. Roche, E.P. Garate, W.W. Heidbrink, and R. McWilliams, Physics of Plasmas, 16, 112509 (2009).
Doppler-Shifted Cyclotron Resonance of Fast Ions with Circularly Polarized Shear Alfven Waves, Y. Zhang, W.W. Heidbrink, S. Zhou, H. Boehmer, R. McWilliams, T.A. Carter, S. Vincena, and M.K. Lilley, Physics of Plasmas, 16, 055706 (2009).
Time-of-Flight Neutral Particle Analyzer and Calibration, W.S. Harris, E.P. Garate, W.W. Heidbrink, R. McWilliams, T. Roche, E. Trask, and Y. Zhang, Review of Scientific Instruments, 79, 10F313 (2008)
Observation of Fast-Ion Doppler-Shifted Cyclotron Resonance with Shear Alfven Waves, Y. Zhang, W.W. Heidbrink, H. boehmer, R. McWilliams, S. Vincena, T.A. Carter, W. Gekelman, D. Leneman, and P. Pribyl, Physics of Plasmas, 15, 102112 (2008).
Spectral Gap of Shear Alfven Waves in a Periodic Array of Magnetic Mirrors, Y. Zhang, W.W. Heidbrink, H. Boehmer, R. McWilliams, G.Y. Chen, B.N. Breizman, S. Vincena, T. Carter, D. Leneman, W. Gekelman, P. Pribyl, and B. Brugman, Physics of Plasmas 15, 012103 (2008)
Laser-Induced Fluorescence Ion Diagnostics in Light of Plasma Processing, R. McWilliams, J.P. Booth, E.A. Hudson, J. Thomas, and D. Zimmerman, Thin Solid Films 515, 4860 (2007)
Convective Flow Zones in Filament-Discharge Plasma Sources, M.J. Brown and R. McWilliams, Journal of Instrumentation 2, P01008 (2007)
Lithium Ion Sources for Investigations of Fast Ion Transport in Magnetized Plasmas, Y. Zhang, H. Boehmer, W.W. Heidbrink, R. McWilliams, D. Leneman, and S. Vincena, Review of Scientific Instruments 78, 013302 (2007)
Diode Laser-Induced Fluorescence Measurements of Metastable Argon Ions in Magnetized Inductively Coupled Plasma, S. Jun, H.Y Chang, and R. McWilliams, Physics of Plasmas 13, 052512 (2006)
A Newly Calibrated Laser-Induced Fluorescence (LIF) System for Ar Ions with a Single Tunable Diode Laser, H.J. Woo, K.S. Chung, T. Lho, R. McWilliams, Journal of the Korean Physical Society 48, 260 (2006)
Determination of Plasma Flow Velocity by Mach Probe and Triple Probe with Correction by Laser-Induced Fluorescence in Unmagnetized Plasmas, Y.S. Choi, H.J. Woo, M.Y. Lee, D. Zimmerman, and R. McWilliams, Japanese Journal of Applied Physics, 45, 5945 (2006)
American Physical Society
American Geophysical Union
Optical Society of America
IEEE - Institute of Electrical and Electronics Engineers