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

5. transient plasma events. Understand the underlying physics and control of high-performance
magnetically confined plasmas sufficiently so that “off-normal” plasma operation, which
could cause catastrophic failure of internal components, can be avoided with high reliability and/
or develop approaches that allow the devices to tolerate some number or frequency of these events.
as plasma energies increase, transient events, which range from periodic edge instabilities
(i.e., edge localized modes — elms) to sudden loss of plasma current (disruptions), will become
a more serious problem for fusion systems, with the potential to disrupt and damage
the device. Preventing or managing them is thus a critical requirement.
6. Plasma modification by auxiliary systems. Establish the physics and engineering science
of auxiliary systems that can provide power, particles, current and rotation at the appropriate locations
in the plasma at the appropriate intensity.
heating, fueling, sustainment and control of fusion plasmas must be carried out by a set of
external systems. examples are heating and current drive systems using waves at various
frequencies or high-energy beams, and frozen pellets for core fueling. The high density and
pressure, and harsh environment, of a demo will be much more challenging for such systems
than present experiments.
7. Magnets. Understand the engineering and materials science needed to provide economic, robust,
reliable, maintainable magnets for plasma confinement, stability and control.
magnets are integral components of all magnetic fusion energy facilities, used for containing
hot plasmas and for all aspects of operation. high-performance superconducting magnets
will be needed for steady-state operation. advances in magnet materials and components,
such as those offered by new high-temperature superconductors, could potentially increase
b and lead to fusion systems that are more attractive in many other respects.
a key distinction between the assessment being carried out by ReneW and the work of the Priorities,
Gaps and opportunities Panel is that the latter primarily assessed gaps that would remain
following the successful completion of iteR and presently planned research. The research activities
identified by ReneW start from the present state of knowledge. For many issues, work is needed
as part of preparation for successful burning plasmas on iteR, while further progress on the
same areas will be needed beyond iteR. There is thus considerable overlap in topics and expertise
between Themes 1 and 2.
in recognition of this, three panels (measurement, control, and transient Plasma events) were
organized jointly with Theme 1. to avoid duplication, these panels first assessed research requirements
for Theme 1, found in the previous chapter, and then additional needs for predictable, highperformance,
steady-state plasmas, found later in this chapter. The combined two sections give a
more complete presentation of the full range of issues and research requirements on those topics.
highlightS oF accoMpliShMENtS
While the emphasis of ReneW is on issues not yet understood, and requirements remaining to be
met, it is important to realize that each of these topical areas is already the subject of considerable
research, and that impressive progress has been made. in this section we provide a few examples
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