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

highly risky in such an environment. This uncertainty alone necessitates a serious rethinking of
how to maintain device integrity, not to mention device control, since these functions for present
devices and for iteR depend heavily upon optical diagnostics.
These measurement challenges must be met in spite of the fact that diagnostic access to the plasma
is being reduced by the need for a high breeding ratio and low streaming loss. in other words, it
is almost certain that a demo will operate with reduced access, with a reduced set of diagnostics,
and with a more self-organized, burning plasma (i.e., one with a reduced sensitivity to external
controls), as compared to iteR and present devices. The steady-state nature of the mission brings
with it additional new challenges for real-time measurement acquisition, interpretation and analysis,
redundancy for crucial measurements, and calibration maintenance.
The following general sub-issues for measurements were explicitly called out in the Fesac Panel
report 1 :
• measurement capability — are the possible measurements adequate to provide necessary
predictive or control capability?
• measurement compatibility — can the measurements be made in the environment of
the device?
• Reliability and calibration — Will the measurements remain trustworthy for the
appropriate time period?
• interpretation and analysis — can the accurate measurements be provided in real time?
mostly OK
some R&D needed
significant R&D needed
Sufficient for present-day tokamaks
Should be sufficient for ITER
measurement
readiness
78
control capable
compatibility
reliability
real-time
interpretation
Should be sufficient for a DEMO
Table 2.1. Assessment of Measurement Research Needs. Note that the “Measurement Capability” subissue
has been split here into the “measurement readiness” and “control capable” columns.
Table 1. Assessment of Measurement Research Needs. Note that the “Measurement Capability” sub-issue
has
Elaboration
been split
of
here
the
into
assessments
the “measurement
of the “measurement
readiness” and “control
readiness”
capable”
and “real-time
columns. Elaboration
interpretation”
of the
for
assessments
present-day of the tokamaks “measurement is necessary. readiness” Present-day and “real-time tokamaks interpretation” have excellent for present-day diagnostic tokamaks capability. is necessary.
However, Present-day additional tokamaks research have and excellent development diagnostic on current capability. devices However, is needed additional in those research categories and to devel- gain
opment crucial on understanding current devices in is specific needed areas in those and categories to perform to gain crucial crucial validation understanding experiments in specific in support areas and of
to future perform needs crucial (see text). validation Hence experiments the “striped” in assessment support of future for those needs categories.
(see text). Hence the “striped” assessment
for those categories.