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

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to stabilize deleterious plasma modes and improve plasma per<strong>for</strong>mance. The key to this ability is<br />

an improved final steering mirror exposed to the plasma. iteR is supporting the development of<br />

several new diagnostics that are able to operate in the neutron environment in iteR. While the<br />

developments needed <strong>for</strong> iteR have driven necessary research, there is still a big gap to a demo<br />

device.<br />

While the progress in taming plasma-material interactions is notable, there is still a large gap to<br />

close be<strong>for</strong>e we are ready to undertake a demo. Greater emphasis needs to be placed on edge plasma<br />

diagnostics and development of physics models of the edge on existing machines. to meet the<br />

expected conditions in future fusion machines, existing laboratory devices <strong>for</strong> basic plasma-material<br />

interaction studies need to be upgraded and new facilities built. innovative solutions that can increase<br />

the capability and robustness of plasma facing components require a new investment of funds<br />

and people. These changes should be coordinated on a national level. Without these changes, the Us<br />

<strong>Fusion</strong> energy sciences Program will not have the knowledge or skills to advance to the next generation<br />

of fusion machines, let alone be ready to participate in demo. as illustrated below, several research<br />

thrusts must cooperate in parallel to build the foundation <strong>for</strong> an integrated experiment leading<br />

to a demo-type device.<br />

<strong>Research</strong> Requirements<br />

The taming the Plasma-material interface participants have identified the following key requirements<br />

and high-leverage candidate investments.<br />

plaSMa-Wall iNtERactioNS<br />

Plasma-wall interactions (PWi) encompass scientific issues that are among the most critical <strong>for</strong><br />

fusion power, affecting: 1) lifetime of PFcs, owing to sputtering and transient erosion, 2) Plasma<br />

contamination by eroded material, 3) tritium co-deposition in eroded and redeposited material,<br />

and 4) operating limits on core plasma (beta, confinement, edge temperature and density, duty<br />

factor, etc.). central to these issues is the science of plasma-material interactions (Pmi). as summarized<br />

in the white papers, there are major gaps in modeling, analysis, and understanding Pmi<br />

phenomena in existing machines, iteR, and certainly post-iteR devices.<br />

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