Abstract Details
Abstracts
Author: Xianzhu Tang
Requested Type: Consider for Invited
Submitted: 2025-02-21 15:08:22
Co-authors: P. Sharma, Y. Li, Y. Zhang, M. Zammit, C. Fontes, J. Colgan
Contact Info:
Los Alamos National Laboratory
Theoretical Division
Los Alamos, NM 87545
USA
Abstract Text:
Plasma power exhaust and particle handling are both critical issues in
steady-state or long-pulse power reactors. In the current short-pulse
machines, both issues appear to be intertwined, but that is not the
case for power reactors. Broadly speaking, particle handling involves
pumping out the unburnt fusion fuel and helium ash in the form of
neutral particles, and controlling wall impurity production due to
plasma-material interaction. The essential requirement is simply
plasma detachment at the divertor plates, which facilitates plasma
recombination at low $T_e$ for pump-out and reduced wall erosion with
low ion impact energies. The enhanced radiation associated with
divertor detachment can reduce the divertor heat load, but the
reduction is rather limited for the closeness of the enhanced
radiation zone to the divertor surface. For plasma power handling in a
power reactor, the challenge is that the plasma wetting area on the
divertor is too small to accommodate the overall plasma power flux
dominated by fusion alpha heating, so it must be radiated onto the
larger area of the first wall. In the current practice of power
reactor designs, that means a radiative mantle or an X-point radiator
(both of seed impurities) much further upstream from the divertor
plates. After a quick review of the current practices, we will take a
deep dive into the collisional-radiative (CR) physics of both atomic
and molecular processes. Of critical importance are the dynamical
processes of impurity injection and wall recycling, both of which are
found to dramatically alter the CR prediction of radiative cooling and
ionization balance. These unusual radiative physics from high to low
plasma temperatures opens new design space that can accommodate the
dual challenges of power-reactor-level plasma power exhaust and
particle handling away from the main body of the plasma, without the
need of either a core radiative mantle or an X-point radiator.
Characterization: 2.0
Comments: