Gerald A. Navratil
510 S.W. Mudd Mail Code: 4714
New York, NY 10027
Phone: +1 212 854 6574
Email:
Interim Dean of SEAS & Thomas Alva Edison Professor of Applied Physics
Research specialty
Plasma physics, plasma diagnostics, fusion energy science
Education
Ph.D. University of Wisconsin, Madison, 1976
Research Interests
My research concentrates on applying experimental plasma physics to the problem of developing controlled thermonuclear fusion as a source of energy. The national research program to develop fusion energy is now more than forty years old and has been receiving substantial amounts of federal funding since the period of energy shortage in the mid-1970's. Fusion energy has the potential to provide a virtually unlimited source of power with a very plentiful fuel supply (deuterium and lithium) and a greatly reduced environmental hazard.
The U. S. Department of Energy funds the High Beta Tokamak Research Program carried out on the HBT-EP tokamak in the Columbia Plasma Physics Laboratory. The objective of this research is to discover what processes limit the stability of a magnetically confined plasma in a tokamak device when the pressure of the plasma becomes comparable with the magnetic field pressure and how to extend these limits to higher pressure. These 'high beta plasmas' are needed to make fusion a practical source of electric power since the fusion power density scales as the square of the plasma pressure.
Our investigations of high-beta plasma physics are carried out on the HBT-EP tokamak located on the Columbia campus and on the Tokamak Fusion Test Reactor (TFTR) located at the nearby Princeton Plasma Physics Laboratory. The HBT-EP tokamak is the third and largest (R = 1 m) in a series of tokamaks built at Columbia and was dedicated in 1993 after a two-year construction period. The unique design of the HBT-EP tokamak includes a 1 cm thick aluminum 'shell' which can be positioned near the plasma edge to provide passive stabilization of pressure-driven plasma instabilities. These passive stabilization techniques are now being studied in combination with the first high-power, active feedback control experiments being carried out with the Los Alamos National Laboratory which has provided a total of 32 megawatts of feedback control power amplifiers for use on HBT-EP.
The work we carried out on the TFTR tokamak, which is the largest fusion facility in the United States, led to the discovery of an improved mode of operation at reduced electric current in the plasma. We have studied these 'high poloidal beta' plasmas using both deuterium-only plasmas and deuterium-tritium plasmas. In our experiments with tritium-fueled plasmas on TFTR, significant amounts of power have been produced which exceeded 6 megawatts of fusion power output.
News
2007 Winner of the John Dawson Award for Excellence in Plasma Physics2006 Fusion Power Associate Leadership Award
2006 Con Edison Lecture: "Bold Step by the World to Fusion Energy: ITER"
Select Publications
"Critical b analyses with ferromagnetic and plasma rotation effects and wall geometry for a high beta; steady state tokamak," G. Kurita, et al. (G.A. Navratil), Nuclear Fusion 46: 383 (2006)"Overview of the National Centralized Tokamak programme," M. Kikuchi, et al. (G.A. Navratil), Nuclear Fusion 46: S29 (2006)
"Measurement of Resistive Wall Mode Stability in Rotating High-Beta DIII-D Plasmas", Reimerdes, Holger et al., (G. A. Navratil), Nuclear Fusion 45: 368 (2005).
"Scaling of the Critical Plasma Rotation for Stabiliation of the n+1 RWM in DIII-D", LaHaye, R.J., A. Bondeson, M.S. Chu, A.M. Garofalo, Y.Q. Liu, G.A. Navratil, M. Okabayshi, H. Reimerdes, and E.J. Strait. Nuclear Fusion 44: 1197 (2004).
"Suppression of resistive wall instabilities with distributed, independently controlled, active feedback coils", Cates, C., et al. (G. A. Navratil). Phys. Plasmas 7:3133-6 (2000).
"Sustained rotational stabilization of DIII-D plasmas above the no-wall beta limit", Garofalo, A. M., et al. (G. A. Navratil). Phys. Plasmas 9:1997 (2002).
"Modeling of active control of external MHD instabilities" Bialek, James, et al. (G. A. Navratil). Phys. Plasmas 8:2170 (2001).
"Active control of 2/1 magnetic islands in a tokamak", Navratil, G. A., et al. Phys. Plasmas 5:1855 (1998).
"Higher fusion power gain with profile control in DIII-D tokamak plasmas", Lazarus, E. A., and G. A. Navratil et al., Nucl. Fusion 37:7 (1997).
"Initial High Beta Operation of the HBT-EP Tokamak", M. K. Vijaya Sankar, E. Eisner, A. Garafalo, D. Gates, T.H. Ivers, R. Kombargi, M. E. Mauel, D. Maurer, D. Nadle, G. A. Navratil, Q. Xiao, J. Fusion Technology 12, 303 (1993).
"High Poloidal Beta Long Pulse Experiments in the Tokamak Fusion Test Reactor", J. Kesner, M. E. Mauel, G. A. Navratil, S. A. Sabbagh, M. Bell, et al., Physics of Fluids B 5, 2525 (1993).
"Operation at the Tokamak Equilibrium Poloidal Beta Limit in TFTR", M. E. Mauel, G. A. Navratil, S. A. Sabbagh, M. G. Bell, et al., Nuclear Fusion 32, 1468 (1992).
"Study of High Poloidal Beta Plasmas in TFTR and DIII-D", by G. A. Navratil, R. A. Gross, M. E. Mauel, S. A. Sabbagh, et al., Plasma Physics and Controlled Fusion Research 1990 (IAEA, Vienna, Austria 1991), Vol. 1, page 209.
"Transition to the Second Region of Ideal MHD Stability", S.A. Sabbagh, M.H. Hughes, M.W. Phillips, A.M.M. Todd, G.A. Navratil, Nuclear Fusion 29, 423 (1989).