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

• build large-size test stands where full-scale internal component tests and design
validations can occur.
• develop and improve first-principle models of the material and plasma coupling for future
fusion machines by validating against new experimental data.
• invest in surface material diagnostics to quantify material behavior and evolution.
• develop and test new surface materials to improve performance margins.
Summary
to address knowledge gaps in the plasma-surface interaction (Psi) for demo, extensive experimental
and theoretical studies are required. This Thrust describes an effort of enhanced modeling,
combined with measurements from both existing and new dedicated Psi test stands, that employ
simple geometries for high-throughput, well-diagnosed material characterization. strengthened
effort in these theoretical simulations, validated properly by data from test stands, can significantly
increase understanding and predictive capabilities of all the Psi processes that affect both
plasma facing components (PFcs) and internal components (ic). advances in plasma-material
interactions (Pmi) research through these new and existing test stands will not only prepare for
demo, but will provide new and exciting opportunities for interactions with the broader materials
research community.
note that this Thrust focuses on the first few micrometers of the materials, whereas Thrust 11
focuses on bulk material innovation and characterization. also, the research from this Thrust
will contribute strongly to and benefit from the enhanced understanding of boundary plasmas
in present devices (Thrust 9) and in a future high-power device (Thrust 12), as well as the nuclear
science of Thrust 13. in addition, the Psi characteristics of some of the advanced materials developed
in Thrust 14 would be tested here.
introduction
Plasma-surface interactions define the boundary condition for any magnetically confined plasma. as device
size and power increase, the limitations to operating regimes become dominant. in iteR the
operating scenarios are already constrained to limit the heat flux to plasma facing armored surfaces,
internal control coils are being added to control intermittent edge localized mode (elm)
events, and concerns have been raised about the heat loads delivered to antennas and launchers.
The functional lifetime of the diagnostic structures necessary to monitor and control the plasma,
and the objects adjacent to them, are uncertain. in larger, higher power, steady-state demo-class
devices, the operational window may be vanishingly small or nonexistent. These imposed limitations
are partially due to an incomplete understanding of both the underlying physics and technology
governing the coupling between the plasma and these adjacent objects.
all present Us confinement facilities use inertially cooled objects surrounding the plasma. This
relatively low-tech approach is suitable because the devices all operate in a short-pulse (< 10s)
fashion. Pulsed operation also allows for conditioning of the plasma facing surfaces between discharges,
and manages Psi for transient achievement of preferred confinement regimes. The technology
encounters new challenges with the use of actively cooled components and longer-pulse
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