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

increasing power density and pulse length also increases the difficulty of handling the heat and
particle fluxes out of the plasma and their impact on the first wall, the emphasis of Theme 3.
Theme 4 addresses many other challenges that must be met for practical fusion energy.
equally important in acquiring the “sufficient state of knowledge,” “with high confidence” is that
the behavior of fusion plasmas and their associated systems be predictable. Progress in scientific
understanding and predictive capability will enable confident extrapolation from present and
planned experiments, including iteR, to next-step devices and demo.
The work of Theme 2 was divided into seven panels, each focused on one of the issues identified
in the resource document, and representing a wide range of expertise in both physics and engineering
science. While these topics are distinct, progress in each is crucial for success in the overall
goal. The panels, Fesac issues, and role in this Theme are outlined briefly below. key research
requirements identified by each panel are detailed in this chapter.
1. Measurement. Make advances in sensor hardware, procedures and algorithms for measurements
of all necessary plasma quantities with sufficient coverage and accuracy needed for the scientific
mission, especially plasma control.
measurements are crucial both for obtaining the needed scientific understanding, and for creating
and controlling steady-state, high-performance plasmas. They will be much more challenging
in a fusion environment than in present experiments.
2. integration of steady-state, high-performance burning plasmas. Create and conduct
research, on a routine basis, of high-performance core, edge and scrape-off layer (SOL) plasmas
in steady state with the combined performance characteristics required for DEMO.
demonstration and study of sustained plasmas in the high-performance regimes envisaged
for practical fusion energy will clearly be required. This will involve integrating both plasma
parameters, and the tools and results of other panels.
3. Validated theory and predictive modeling. Through developments in theory and modeling,
and careful comparison with experiments, develop a set of computational models that are capable
of predicting all important plasma behavior in the regimes and geometries relevant for practical
fusion energy.
The predictive capability embodied in a comprehensive set of well-validated models will
guide the experimental demonstrations and represent the plasma physics knowledge base
for proceeding to develop fusion energy.
4. Control. Investigate and establish schemes for maintaining high-performance burning plasmas
at a desired, multivariate operating point with a specified accuracy for long periods, without disruption
or other major excursions.
maintaining plasmas in high-performance states, which may be above passive stability
limits, requires many plasma parameters and profiles, with myriad interactions, to be controlled
simultaneously. This needs to be accomplished with higher reliability and more limited
external power than in present experiments.
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