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

ment of a program that, in collaboration with the iteR team, would continually reevaluate the
physics and engineering measurement requirements in iteR as they change in response to evolving
understanding and capability. Research needs would be identified when the iteR measurements
requirements are judged to be at high risk of being unmet. in combination with this on-going
assessment, we also identify these specific research needs:
• Research on and development of new techniques to address existing measurement gaps,
e.g., dust, lost alpha particles, edge flows.
• Research to reduce risk on the measurement capabilities of planned techniques, due to the
iteR environment. The primary example of such a risk is the first mirror, for which there
are concerns about lifetime and stability. There are also uncertainties in the estimates of
lifetimes and performance of in-vessel sensors, cables, and connectors that are too large.
These issues connect to many independent diagnostic systems.
• Research to develop new techniques that use robust plasma front end interfaces, e.g.,
microwave and X-ray techniques.
• Research to develop calibration strategies and reliability requirements.
Development of the necessary degree of real-time interpretation and analysis of measurements
in this area we identify the following research needs.
Develop real-time measurement and analysis capability
Reactor-relevant burning plasmas will operate for long times, and measurements will need to be
available continuously to optimize performance. control systems will require the availability of
real-time measurements to control actuator systems. significant progress in this area has allowed
for real-time measurement of plasma profiles and equilibria in present devices. These techniques
will need to be significantly advanced, expanded, and tested for application to burning plasmas.
Performance optimization requires real-time adjustment of temperature, density, and current
density profiles. different operational scenarios have different real-time measurement and feedback
requirements. For example, advanced scenarios (with high beta and high bootstrap fraction)
will likely be most demanding in real-time analysis.
This research need is to be coordinated with integrated Plasma control research.
Develop strategies and techniques for prediction, rapid evaluation, decision for prevention, mitigation
of disruptions/off-normal events required for machine operation and protection
any long-pulse plasma experiment will need to confront off-normal events such as disruptions,
which can ablate and melt first-wall materials, drive large halo currents, create runaway electrons,
and put stress on structural components. numerous techniques are being developed to
mitigate the adverse effects of disruptions. implementing such systems on burning plasma experiments
will be a special challenge to the interpretation and analysis of measurements. equally
important is the necessity to prevent off-normal events from occurring in the first place. This re-
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