### Research Experience

- Research Associate, Princeton University Plasma Physics Lab, 1973-1974
- Physicist, Fusion Energy Sciences Program, LLNL, 1974-present
- Associate Program Leader and MFE Theory Group Leader, LLNL, 1988-2006

Ronald Cohen is a theoretical and computational plasma physicist with general interests in plasma physics for magnetic fusion and heavy-ion fusion applications, accelerator physics, nonlinear dynamics, computational fluid dynamics, astrophysics, and space plasmas. Specific MFE plasma physics areas of concentration have included tokamak edge physics radio frequency-plasma interactions, magnetic mirror confinement, and spheromak physics. He ws co-PI of the team that won the Gordon Bell Prize for computational performance in 1999. He is a fellow of the American Physical Society, and has over 160 refereed publications.

### Selected Publications

I. Joseph, **R.H. Cohen**, and D.D. Ryutov, "Driving toroidally asymmetric current through the tokamak scrape-off layer to suppress edge localized modes", **16**, 052510 (2009).

**R.H. Cohen**, D.P. Grote, A. Friedman, and J.-L. Vay, "An Implicit ``Drift-Lorentz'' Mover for Plasma and Beam Simulations", **53** (2009).

**R.H. Cohen** and X.Q. Xu, "Progress in Kinetic Simulation of Edge Plasmas", Contributions to Plasma Physics **48**, 212 (July 2008) (invited review).

**R.H. Cohen**, B. LaBombard, D.D. Ryutov, J.L. Terry, M.V. Umansky, X.Q. Xu, S. Zweben, "Theory and Fluid Simulations of Boundary Plasma Fluctuations", **47**, 612 (2007).

**R.H. Cohen**, D.D. Ryutov, G.F. Counsell, and P. Helander, "Current and Potential Distribution with Toroidally Asymmetric Biasing of the Divertor Plate", **49**, 1 (2007).

**R.H. Cohen** and D.D. Ryutov, "Dynamics of an isolated blob in the presence of the X-point", Contrib. to **46**, 678 (2006).

**R.H. Cohen** and D.D. Ryutov, "On the possibility of the sheath-driven, finite-beta modes localized near the divertor plate", **47**, 1187 (2005).

**R.H. Cohen**, A. Friedman, M. Kireeff Covo, S.M. Lund, A.W. Molvik, F.M. Bieniosek, F. P.A. Seidl, J.-L. Vay, P. Stoltz, and S. Veitzer, "Simulating Electron Clouds in Heavy-Ion Accelerators," **12**, 056708 (2005).

**R.H Cohen** and D.D Ryutov, "Sheath Physics and Boundary Conditions for Edge Plasmas", **44**, 111 (2004) (invited review paper).

Shestakov, A. I., **Cohen, R. H.**, Crotinger, J. A., LoDestro, L. L., Tarditi, A. and Xu, X. Q., "Self-Consistent Modeling of Turbulence and Transport," **185**, 399-426 (2003).

**Cohen, R. H.**, Dannevik, W. P., Dimits, A. M., Eliason,D., Mirin, A. A., Zhou, Y., Porter, D. H. and Woodward, P. R., "Three-dimensional simulation of a Richtmyer-Meshkov instability with a two-scale initial perturbation." **14**, 3692 (2002).

**Cohen, R.H.**, Ryutov, D.D., "Discrete symmetries in axisymmetric toroidal plasma confinement," **8**, 1451 (2001).