# Uri Shumlak

####
Professor

Aeronautics & Astronautics

Adjunct Professor

Applied Mathematics

Associate Chair for Academics

Aeronautics & Astronautics

- shumlak@uw.edu
- (206) 616-1986
- AER 432
- Faculty Website
- Flow Z-Pinch Lab
- Computational Plasma Dynamics Lab
- Curriculum Vitae

## Biography

Professor Shumlak completed his undergraduate work at Texas A & M University and then obtained his PhD from the University of California at Berkeley. After finishing his graduate degree, he was a National Research Council Postdoctoral Fellow at the Air Force Phillips Laboratory (now AFRL) at Kirtland AFB. After the Phillips Lab, he joined the Aeronautics and Astronautics Department at the University of Washington where he is currently a Professor and serves as the department’s Associate Chair for Academics. He is also an Adjunct Professor of Applied Mathematics. He is an APS Fellow, an IEEE Fellow, and an AIAA Associate Fellow. He has also co-founded Zap Energy – a spin-out company from the University of Washington to develop commercial nuclear fusion.

Prof. Shumlak’s research areas are fundamental plasma physics, theoretical and computational plasma modeling, innovative magnetic plasma confinement for fusion energy, and advanced space propulsion. He develops plasma modeling algorithms that use high-order finite element methods for studying plasma dynamics. The algorithms are implemented in the WARPXM (Washington Approximate Riemann Plasma eXtended Modeling) code framework developed by his research group to solve MHD, 5N-moment multi-fluid, and multi-species continuum kinetic plasma models. His work includes theoretical and experimental investigations of the stabilizing effect of sheared flows in magnetically confined plasmas. A sheared-flow-stabilized Z pinch would have immediate applications as a compact fusion energy source and as a fusion space thruster. He has also developed the flow Z-pinch concept into an extreme ultraviolet (EUV) light source for next generation semiconductor lithography.

## Education

- PhD, University of California at Berkeley
- BS, Texas A&M University

## Current projects

**Flow Z-Pinch Lab**

The flow Z-pinch is an innovative concept to magnetically confine a high-temperature, high-density plasma. The Z-pinch has a simple, linear configuration with no applied magnetic fields. The self-field generated by the axial current confines and compresses the plasma. The static Z-pinch was investigated extensively for fusion energy applications; however, the configuration was found to be unstable to gross sausage and kink modes. The flow Z-pinch introduces an axial plasma motion that can mitigate these instabilities.

The Flow Z-Pinch Lab includes the original ZaP Flow Z-Pinch, ZaP-HD (High Energy Density), and FuZE (Fusion Z-Pinch) Experiments.

The research project investigates the concept of using sheared axial flows to provide complete stability without adversely affecting the advantageous properties of the Z-pinch (no applied fields, high temperatures, high densities, unity average beta, and only perpendicular heat conduction). The experiments produce Z-pinch plasmas that are 50 – 130 cm long with 0.3 – 1.5 cm radii. The plasmas exhibit stability for extended quiescent periods. The project seeks to address basic plasma science questions associated with the connection between sheared flows and plasma stability and with the interface of high energy density plasma in contact with solid or liquid materials. The sheared-flow-stabilized Z-pinch has applications for compact fusion energy and for advanced space propulsion.

**Computational Plasma Dynamics Lab**

Material heated to a sufficiently high temperature will ionize and form a plasma. Plasmas consist of electrons, ions, and neutrals, which interact through short-range intra-species and inter-species collisions. The plasma’s charged species also generate and interact with long-range electric and magnetic fields. The ability to exert long-range body forces allows remote manipulation that includes magnetic confinement of high energy density plasmas for fusion energy and electromagnetic acceleration to high speeds for plasma propulsion.

Modeling plasma dynamics is uniquely challenging. Complete N-body calculations are precluded by the large number of particles in most plasmas, typically N is O(1023) with O(N2) interactions among charged species. Statistical approaches can alleviate the difficulty introduced by the large number of particles. However, the different masses of the plasma species lead to vastly disparate temporal and spatial scales.

The challenge of multiple scales is further exacerbated in nearly all plasma devices because the plasmas are much larger than any intrinsic spatial scale and operate for much longer than any intrinsic temporal scale. The multi-scale nature of plasmas can be addressed through mathematical reduction by applying asymptotic approximations to higher fidelity models to produce computationally tractable models that retain the relevant physical mechanisms.

We develop novel computational algorithms that simulate plasma dynamics with high-order accuracy using high-fidelity plasma models.

The plasmas are modeled with the magnetohydrodynamic (MHD) model and by more physically complete multi-fluid and kinetic plasma models. Multi-fluid and multi-species models allow for separate treatment of plasma and neutral constituents. The algorithms are implemented on parallel supercomputers using the message passing interface (MPI).

The codes are applied to study computational plasma science and develop insight into plasma phenomena. Codes developed include a 3-D MHD code, WARP3, a co-located electrodynamics code that includes current sources, WARP4, and a full multi-fluid (electron, ion, neutrals, impurities, …) code, WARPX, a continuum kinetic code WARPM, and a framework for the multi-fluid and multi-species continuum kinetic plasma models for unstructured grids, WARPXM. The codes and models are coupled to form hybrid combinations.

## Select publications

- U. Shumlak, E.T. Meier, and B.J. Levitt. Fusion Gain and Triple Product for the Sheared-Flow-Stabilized Z Pinch. Fusion Science and Technology 80, 1 (2024)
- I.A.M. Datta and U. Shumlak. Computationally efficient high-fidelity plasma simulations by coupling multi-species kinetic and multi-fluid models on decomposed domains. Journal of Computational Physics 482, 112073 (2023)
- D.W. Crews, and U. Shumlak. On the validity of quasilinear theory applied to the electron bump-on-tail instability. Physics of Plasmas 29, 043902 (2022)
- E.T. Meier and U. Shumlak. Development of five-moment two-fluid modeling for Z-pinch. Physics of Plasmas 28, 092512 (2021)
- I.A.M. Datta, D.W. Crews, and U. Shumlak. Electromagnetic extension of the Dory-Guest-Harris instability as a benchmark for Vlasov-Maxwell continuum kinetic simulations of magnetized plasmas. Physics of Plasmas 28, 072112 (2021)
- U. Shumlak. Z-Pinch Fusion. Journal of Applied Physics 127, 200901 (2020) [Featured Article, Invited Perspectives Article]
- G.V. Vogman, J.H. Hammer, U. Shumlak, and W.A. Farmer. Two-fluid and kinetic transport physics of Kelvin-Helmholtz instabilities in nonuniform low-beta plasmas. Physics of Plasmas 27, 102109 (2020)
- Y. Zhang, U. Shumlak, B.A. Nelson, R.P. Golingo, T.R. Weber, A.D. Stepanov, E.L. Claveau, E.G. Forbes, Z.T. Draper, J.M. Mitrani, H.S. McLean, K.K. Tummel, D.P. Higginson, and C.M. Cooper. Sustained neutron production from a sheared-flow stabilized Z-pinch. Physical Review Letters 122, 135001 (2019) [Featured Article]
- A. Ho, I.A.M. Datta, and U. Shumlak. Physics-Based-Adaptive Plasma Model for High-Fidelity Numerical Simulations. Frontiers in Physics 6, 105 (2018)
- G.V. Vogman, U. Shumlak, and P. Colella. Conservative fourth-order finite-volume Vlasov-Poisson solver for axisymmetric plasmas in cylindrical (r, vr, vtheta) phase space coordinates. Journal of Computational Physics 373, 877 (2018)
- U. Shumlak, B.A. Nelson, E.L. Claveau, E.G. Forbes, R.P. Golingo, M.C. Hughes, R.J. Oberto, M.P. Ross, and T.R. Weber. Increasing plasma parameters using sheared flow stabilization of a Z-pinch. Physics of Plasmas 24, 055702 (2017) [Invited Article]
- E.M. Sousa and U. Shumlak. A blended continuous – discontinuous finite element method for solving the multi-fluid plasma model. Journal of Computational Physics 326, 56 (2016)
- U. Shumlak, J. Chadney, R.P. Golingo, D.J. Den Hartog, M.C. Hughes, S.D. Knecht, W. Lowrie, V.S. Lukin, B.A. Nelson, R.J. Oberto, J.L. Rohrbach, M.P. Ross, and G.V. Vogman. The Sheared-Flow Stabilized Z-Pinch. Fusion Science and Technology 61, 119 (2012)
- E.T. Meier and U. Shumlak. A general nonlinear fluid model for reacting plasma-neutral mixtures. Physics of Plasmas 19, 072508 (2012)
- U. Shumlak, R. Lilly, N. Reddell, E. Sousa, and B. Srinivasan. Advanced physics calculations using a multi-fluid plasma model. Computer Physics Communications 182, 1767 (2011)
- U. Shumlak, C.S. Adams, J.M. Blakely, B.-J. Chan, R.P. Golingo, S.D. Knecht, B.A. Nelson, R.J. Oberto, M.R. Sybouts, and G.V. Vogman. Equilibrium, flow shear and stability measurements in the Z-pinch. Nuclear Fusion 49 (7), 075039 (2009)
- U. Shumlak and J. Loverich. Approximate Riemann solver for the two-fluid plasma model. Journal of Computational Physics 187 (2), 620 (2003)
- U. Shumlak, R.P. Golingo, B.A. Nelson, and D.J. Den Hartog. Evidence of stabilization in the Z pinch. Physical Review Letters 87 (20), 205005 (2001)
- U. Shumlak and N.F. Roderick, Mitigation of the Rayleigh-Taylor instability by sheared axial flows. Physics of Plasmas 5 (6), 2384 (1998)
- U. Shumlak and C.W. Hartman. Sheared Flow Stabilization of the m=1 Kink Mode in Z-Pinches. Physical Review Letters 75 (18), 3285 (1995)

## Honors & awards

- Erna and Jakob Michael Visiting Professorship, Weizmann Institute of Science, 2018
- Faculty Scholar, Lawrence Livermore National Laboratory, 2018
- Graduate Educator of the Year (Aeronautics & Astronautics, University of Washington, Seattle, WA), 2022
- Graduate Educator of the Year (Aeronautics & Astronautics, University of Washington, Seattle, WA), 2016
- Faculty Innovator Award (College of Engineering, University of Washington), 2011
- Abe Zarem National Graduate Educator Award (American Institute of Aeronautics and Astronautics), 2003
- Professor of the Year (Aeronautics & Astronautics, University of Washington), 2002
- Certificate of Recognition by the University of Washington’s Minority Science & Engineering ALVA Program (Alliances for Learning and Vision for Underrepresented Americans), 2000
- Professor of the Year (Aeronautics & Astronautics, University of Washington), 1999
- National Research Council Fellow, National Academy of Sciences, 1992
- Fellow, American Physical Society 2019
- Fellow, Institute of Electrical and Electronics Engineers 2023
- Associate Fellow, American Institute of Aeronautics and Astronautics 2016