Research Needs for Magnetic Fusion Energy Sciences - US Burning ...

In the discussion below, key research opportunities and requirements identified by the panel are described
according to topical science area. It should be noted, though, that many of the opportunities lie in the integration
of multiple topical areas.
Core Plasma Physics (including transport and MHD Stability)
Science Opportunities:
• how do we tailor the pressure and current profiles to achieve optimized steady-state
burning plasma tokamak operation in which self-heating dominates?
• how can we produce high-performance, quiescent, steady-state plasmas?
• What physics governs transport of fusion fuel and reaction products as well as wallgenerated
impurities? What causes core transport barrier formation?
• how rapidly will large reactor plasmas rotate, and what effect does rotation have on
performance limits?
research requirements
Progress here requires advances in theory, modeling, and experiment. an analytic understanding
of underlying first-principles physics models is required for verification of models. advances
in treating multi-scaled or multi-physics problems are needed. For example, improved coupling
of transport-mhd and RF-fast particle physical processes for predictive profile evolution
and steady-state operations are needed. systematic development of such a capability should be
planned, in collaboration with analytic theory, development of reduced integrated modeling, and
dedicated experimental validation efforts that include synthetic diagnostic development.
Edge/Scrape-off Layer (SOL)/Divertor Plasma Physics
Science Opportunities:
• What are the power and particle loads on divertor plates and first wall in a highperformance
plasma?
• how will a fully steady-state reactor-relevant wall affect the core plasma performance,
and what approaches can be used to control the erosion, transport, and redeposition of
wall material?
• how do we adequately fuel the plasma and remove fusion reaction byproducts?
• how do we manage and control the tritium inventory in a steady-state reactor?
research requirements
significant advances in theory, modeling, and experiment are needed to address the science opportunities
listed above. Particularly challenging, given large fluctuation amplitudes and a lack
of clear scale separation, are the calculation of self-consistent electric fields and self-generated
flows, and the proper treatment of open field lines. in addition, improved models for sheath physics,
including radiofrequency and kinetic effects and sol/first-wall/antenna geometry, and physics-based
models for plasma-wall interaction, including multi-scale material physics, chemistry,
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