Research Interests

Bruce Cohen is a theoretical and computational plasma physicist with general interests in plasma physics, fluid mechanics and hydrodynamics, statistical mechanics, and electromagnetics. Specific plasma physics experience: laser fusion and radio-frequency heating parametric instabilities, nonlinear beat-wave processes, particle simulation, linear and nonlinear theory of microinstabilities, turbulent velocity space transport, finite-Larmor-radius theory of magnetohydrodynamics, and multiple-time-scale computational methods. Over 160 refereed publications.

Previous LLNL Experience

• Associate Program Leader for Theory and Computations (2007–2016)
• Fusion Energy Program
• Physicist (1976–January 2017)
• Subcontractor Physicist (2017-present)

PhD, Physics, University of California, Berkeley, 1975

MA, Physics, University of California, Berkeley, 1972

BS, Physics, Harvey Mudd College (graduated with honors & distinction), 1970

Selected Publications

A. N. Kaufman and B. I. Cohen, Theoretical Plasma Physics, J. Plasma Phys. 85, Issue 6, 205850601 (2019). doi: 10.1017/S0022377819000667

B. I. Cohen, A. M. Dimits, G. B. Zimmerman, and S. C. Wilks, One-dimensional particle simulations of Knudsen-layer effects on D-T fusion, Phys. Plasmas 21, 122701 (2014), doi: 10.1063/1.4903323

B. I. Cohen, A. M. Dimits, L. Divol, F. Fiuza, A. J. Kemp, and D. J. Strozzi, A PIC-Fluid Hybrid Algorithm for Multi-scale Simulations of Laser-plasma Interactions, IEEE Trans. Plasma Sci. 42, 1335 (2014), doi: 10.1109/PLASMA.2013.6633429

B. I. Cohen, M. V. Umansky, W. M. Nevins, M. A. Makowski, J. A. Boedo, D. Rudakov, G. M. McKee, Z. Yan, and R. J. Groebner, Simulations of drift resistive ballooning L-mode turbulence in the edge plasma of the DIII-D tokamak, Phys. Plasmas 20, 055906 (2013), doi: 10.1063/1.4804638

B. I. Cohen, A. M. Dimits, A. Friedman, and R. E. Caflisch, Time-step Considerations in Particle Simulation Algorithms for Coulomb Collisions in Plasmas, IEEE Trans. Plasma Sci. 38, 9, 2394 (2010), doi: 10.1109/TPS.2010.2049589

B. I. Cohen, C. A. Romero-Talamas, E. B. Hooper, L. L. Lodestro, D. Ryutov, H. S. McLean, T. L. Stewart, and R. D. Wood, The Role of the n_ϕ = 1 Column Mode in Spheromak Formation, Phys. Plasmas 16, 042501 (2009), doi: 10.1063/1.3097909

B. I. Cohen, L. Divol, A.B. Langdon, and E.A. Williams, Effects of Ion-ion Collisions and Inhomogeneity in 2D Simulations of Stimulated Brillouin Backscattering, Phys. Plasmas 13, 022705 (2006), doi: 10.1063/1.2201028

B. I. Cohen, E.B. Hooper, R.H. Cohen, D.N. Hill, H.S. McLean, R.D. Wood, and S. Woodruff, C.R. Sovinec, and G.A. Cone, Simulation of Spheromak Evolution and Energy Confinement, Phys. Plasmas 12, 056106 (2005), doi: 10.1063/1.1869501

C. R. Sovinec, B. I. Cohen, G. A. Cone, E. B. Hooper, and H. S. McLean, Numerical Investigation of Transients in the SSPX Spheromak, Phys. Rev. Lett. 94, 035003 (2005), doi: 10.1103/PhysRevLett.94.035003

B. I. Cohen, A.M. Dimits, W.M. Nevins, Y. Chen, and S. Parker, Kinetic Electron Closures for Electromagnetic Simulation of Drift and Shear-Alfvén Waves, Phys. Plasmas, 9, 251 (2002), doi: 10.1063/1.1428759

B. I. Cohen and A.M. Dimits, Implicit, Partially Linearized Electromagnetic Particle Simulation of Plasma Drift-wave Turbulence, Phys. Rev. E 56, 2151 (1997)

B. I. Cohen, D. C. Barnes, J. M. Dawson, et al., The Numerical Tokamak Project: Simulation of Turbulent Transport, Comp. Phys. Commun. 87, 1 (1995), doi: 10.1016/0010-4655(94)00166-Y

B. I. Cohen, R. H. Cohen, W.M. Nevins, and T.D. Rognlien, Theory of Free-Electron-Laser Heating and Current Drive in Magnetized Plasmas, Reviews of Modern Physics, 63, 949 (1991), doi: 10.1103/RevModPhys.63.949

J.U. Brackbill and B. I. Cohen, eds., Multiple Time Scales, Computational Techniques, Academic Press Inc., 1985 (author of Chapt. 10: “Orbit Averaging and Subcycling”)

B. I. Cohen and J. Killeen, “Computations in Plasma Physics”, Physics Today 36, 54 (1983), doi: 10.1063/1.2915659

Honors and Awards

• National Science Foundation Fellow (1970–73)
• Woodrow Wilson Foundation Fellow (1970–71)
• American Physical Society Fellow, Division of Plasma Physics (elected 1987)
• LLNL Physical Sciences Distinguished Achievement Award for Outstanding Scientific Publication (1993)
• LLNL Weapons Complex Integration Award for Outstanding Report (L2 Milestone Research on Knudsen Layer and Diffusivity Effects), 2014
• IEEE NPPS Charles K. Birdsall Computational Science Award 2018