Research Needs for Magnetic Fusion Energy Sciences Report of the Research Needs Workshop (ReNeW) Bethesda, Maryland – June 8-12, 2009 OFFICE OF FUSION ENERGY SCIENCES 1 ON THE COVER Depicted is Vortex Waltz, a computer simulation snapshot of two-dimensional fluid vortexes captured by J. Luc Pe- terson (graduate student) and Greg Hammett (physicist) at the Princeton Plasma Physics Laboratory, Princeton University. Two-dimensional fluid vortexes attract, swirling and merging with their partners in a turbulent ballet. This natural behavior influences phenomena ranging from weather patterns in the atmosphere to the performance of nuclear fusion devices. Advanced numerical algorithms and high-performance supercomputers allow for turbu- lence simulations of unprecedented detail. This snapshot catches the vortexes in the act. Originally entirely sepa- rated, the two vortex centers (dark red) have sent out spiral bands and shock waves throughout the background fluid as they’ve circled each other and combined. If left alone long enough, the two will complete their dance as a single, larger vortex. The image is featured in the 2009 Art of Science exhibit at Princeton University. Research Needs for Magnetic Fusion Energy Sciences Report of the Research Needs Workshop (ReNeW) ReNeW is a planning activity of the Office of Fusion Energy Sciences (OFES) Chair: RICHARD HAZELTINE, The University of Texas at Austin Vice-Chair: DAVID HILL, Lawrence Livermore National Laboratory OFES: HUTCH NEILSON, Office of Fusion Energy Sciences, U.S. Department of Energy* Theme Leaders: CHARLES GREENFIELD, General Atomics AMANDA HUBBARD, Massachusetts Institute of Technology RAJESH MAINGI, Oak Ridge National Laboratory WAYNE MEIER, Lawrence Livermore National Laboratory RENE RAFFRAY, University of California, San Diego JOHN SARFF, University of Wisconsin-Madison MICHAEL ULRICKSON, Sandia National Laboratories JAMES W. VAN DAM, The University of Texas at Austin MICKEY WADE, General Atomics MICHAEL ZARNSTORFF, Princeton Plasma Physics Laboratory OFES Contacts: SAM BARISH, Office of Fusion Energy Sciences, U.S. Department of Energy ROSTOM DAGAZIAN, Office of Fusion Energy Sciences, U.S. Department of Energy MARK FOSTER, Office of Fusion Energy Sciences, U.S. Department of Energy JOHN MANDREKAS, Office of Fusion Energy Sciences, U.S. Department of Energy AL OpDENAKER, Office of Fusion Energy Sciences, U.S. Department of Energy BArrY SuLLIVAN, Office of Fusion Energy Sciences, U.S. Department of Energy PUBLICATION Editor: PATTI WIESER, Princeton Plasma Physics Laboratory Design/Layout: GREGORY CZECHOWICZ, Princeton Plasma Physics Laboratory Support: LISA GLOUDON, Princeton Plasma Physics Laboratory Web Support: JAMES DEKOCK, University of Wisconsin-Madison EMILY HOOKS, The University of Texas at Austin *On detail to OFES from Princeton Plasma Physics Laboratory. 2 TABLE OF CONTENTS Executive Summary ............................................................................................................................................................. 5 PART I: Issues and Research Requirements ..................................................................................................................... 19 Theme 1:B urning Plasmas in ITER ....................................................................................................................... 25 Theme 2:C reating Predictable, High-Performance, Steady-State Plasmas ....................................................... 71 Theme 3:T aming the Plasma-Material Interface ...............................................................................................123 Theme 4:H arnessing Fusion Power..................................................................................................................... 141 Theme 5:O ptimizing the Magnetic Configuration ............................................................................................ 171 PART II: Research Thrusts ...............................................................................................................................................233 Thrust 1: D evelop measurement techniques to understand and control burning plasmas ........................235 Thrust 2: Control transient events in burning plasmas .................................................................................. 243 Thrust 3: Understand the role of alpha particles in burning plasmas ...........................................................251 Thrust 4: Qualify operational scenarios and the supporting physics basis for ITER. ..................................257 Thrust 5: E xpand the limits for controlling and sustaining fusion plasmas ................................................265 Thrust 6: D evelop predictive models for fusion plasmas, supported by theory and challenged with experimental measurement .............................................................................................................277 Thrust 7: E xploit high-temperature superconductors and other magnet innovations to advance fusion research ...................................................................................................................................285 Thrust 8: Understand the highly integrated dynamics of dominantly self-heated and self-sustained burning plasmas .................................................................................................................................293 Thrust 9: Unfold the physics of boundary layer plasmas ................................................................................301 Thrust 10: Decode and advance the science and technology of plasma-surface interactions ......................311 Thrust 11: Improve power handling through engineering innovation ........................................................... 319 Thrust 12: Demonstrate an integrated solution for plasma-material interfaces compatible with an optimized core plasma ..................................................................................................................325 Thrust 13: Establish the science and technology for fusion power extraction and tritium sustainability ..333 Thrust 14: Develop the material science and technology needed to harness fusion power ..........................341 Thrust 15: Create integrated designs and models for attractive fusion power systems ...............................351 Thrust 16: Develop the spherical torus to advance fusion nuclear science .....................................................359 Thrust 17: Optimize steady-state, disruption-free toroidal confinement using 3-D magnetic shaping, and emphasizing quasi-symmetry principles .................................................................................369 Thrust 18: Achieve high-performance toroidal confinement using minimal externally applied magnetic field .....................................................................................................................................379 Appendix A: Acronyms and Abbreviations ...............................................................................................................389 Appendix B: Workshop Schedule ...............................................................................................................................395 Appendix C: Theme Workshops ..................................................................................................................................396 Appendix D: White Papers ...........................................................................................................................................397 Appendix E: ReNeW Participants ...............................................................................................................................413 3 4 EXECUTIVE SUMMARY Nuclear fusion — the process that powers the sun — offers an environmentally benign, intrinsi- cally safe energy source with an abundant supply of low-cost fuel. It is the focus of an internation- al research program, including the ITER fusion collaboration, which involves seven parties repre- senting half the world’s population. The realization of fusion power would change the economics and ecology of energy production as profoundly as petroleum exploitation did two centuries ago. The 21st century finds fusion research in a transformed landscape. The worldwide fusion commu- nity broadly agrees that the science has advanced to the point where an aggressive action plan, aimed at the remaining barriers to practical fusion energy, is warranted. At the same time, and largely because of its scientific advance, the program faces new challenges; above all it is chal- lenged to demonstrate the timeliness of its promised benefits. In response to this changed landscape, the Office of FusionE nergy Sciences (OFES) in the US De- partment of Energy commissioned a number of community-based studies of the key scientific and technical foci of magnetic fusion research. The Research Needs Workshop (ReNeW) for Magnetic Fusion Energy Sciences is a capstone to these studies. In the context of magnetic fusion energy, ReNeW surveyed the issues identified in previous studies, and used them as a starting point to de- fine and characterize the research activities that the advance of fusion as a practical energy source will require. Thus, ReNeW’s task was to identify (1) the scientific and technological research fron- tiers of the fusion program, and, especially, (2) a set of activities that will most effectively advance