**Robert J. Goldston**

Professor of Astrophysical Sciences

goldston@pppl.gov

609-243-3550

**Inertial Confinement Fusion R&D and Nuclear Proliferation**

**Education**

- B.A., Physics, Harvard University, 1972
- Ph.D., Astrophysical Sciences, Program in Plasma Physics, Princeton University, 1977

**Research Interests**

I started my research career studying how plasmas are heated by energetic ions. I did experimental research on fast ion thermalization in tokamaks, finding for example classical slowing down and pitch angle scattering, including onto banana orbits. I developed the first version of the now world-standard Monte Carlo code to calculate neutral beam heating. I did theoretical calculations on the effects of toroidal field ripple on fast ions and alpha particles, finding an equivalent to the Chirikov overlap criterion. I also found the first fast-ion instability in a tokamak, the “fishbone”, and explained its resonance interaction with fast ions due to a drift-precession resonance.

This work evolved into research on energy confinement in tokamaks. I found that a remarkable reproducibility in the reported experimental scalings, and develop a scaling relation that predicted the operation of the next generation of large tokamaks (TFTR, JET, JT-60) with surprising accuracy. I pointed out that these results were consistent in magnitude and general scaling with what I called “Gyro-reduced Bohm” (now called Gyro-Bohm) transport to be expected from drift-wave turbulence. I then worked on the design of next-step experimental devices: BPX, TPX and NSTX.

My research activities were interrupted for 12 years by my responsibilities as Director of PPPL. We finished the clean-up of TFTR, got NSTX operating, moved PPPL into the forefront of advanced computing, and launched ITER. We were not able to complete the construction of a new stellarator, NCSX, but instead launched a major upgrade for NSTX.

Since stepping down as Director in 2009 I have continued to follow the energy flow in fusion to what I consider now to be the most crucial area, the plasma-material interface. Recently I developed a heuristic drift-based theory for the scrape-off layer width in tokamaks that predicts with remarkable accuracy both the magnitude and scaling that has been measured on ASDEX-Upgrade, C-MOD, DIII-D, JET and NSTX. I am also interested in the physics and engineering of liquid metal, particularly lithium, plasma-facing components. Liquid metals are self-healing, apparently thermally self-shielding, and lithium in particular is so low-Z that it neither radiates from the plasma core nor is pulled into the plasma by neoclassical forces.

A major parallel interest of mine has been nuclear nonproliferation as it applies to both fission and fusion energy systems. I have also begun to work on a “Zero-Knowledge” approach to verifying nuclear warheads as part of disarmament.

**Awards & Honors**

- Fellow of the American Physical Society
- Excellence in Plasma Physics

**Teaching**

AST 309 Science and Technology of Nuclear Energy: Fission and Fusion

**Selected Publications**

- Eich, T. et al . Inter-ELM Power Decay Length for JET and ASDEX Upgrade: Measurement and Comparison with Heuristic Drift-Based Model.
*Phys. Rev. Lett.***107**, 215001 (2011). - Glaser, A. & Goldston, R. J. Proliferation risks of magnetic fusion energy: clandestine production, covert production and breakout.
*Nucl Fusion***52**, 043004 (2012). - Goldston, R. J. Heuristic drift-based model of the power scrape-off width in low-gas-puff H-mode tokamaks.
*Nucl Fusion***52**, 013009 (2012). - Goldston, R. J. When is it valid to assume that heat flux is parallel to B? J.
*Nucl. Mater.***415**, S566-S569 (2011). - Goldston, R. J. Climate Change, Nuclear Power, and Nuclear Proliferation: Magnitude Matters.
*Science & Global Security***19**, 130-165 (2011). - Goldston, R. J. Downstream heat flux profile versus midplane T profile in tokamaks.
*Phys Plasmas***17**, 012503 (2010).