Speaker
Dr
Xianzhu Tang
(Los Alamos National Laboratory)
Description
The divertor and first wall surface not only recycles the plasma particles
as returned neutrals
but also returns a portion of the impacting ion kinetic energy to the
plasma. Unlike carbon tiles, tungsten walls, for the much larger atomic mass,
mostly reflect the impacting light ions and hence recycle a majority
of the plasma ion kinetic energy.
This hinders the plasma energy exhaust and affects the application of external
controls for radiative cooling of the boundary plasma.
We have carried out a combination of molecular dynamics simulations and plasma
kinetic simulations, together with theoretical analysis,
to understand how the plasma sheath and the tungsten recycling characteristics,
determine the net plasma power exhaust in terms of the density the temperature
of the boundary plasma.
The new findings include insights on Bohm criterion which predicts a plasma exit speed that
is robustly higher than local sound speed in conventional analysis, and on electron heat flux
that is a major component of the plasma energy exhaust flux.
More importantly, they point out ways for engineering control of the plasma power exhaust.
| Country or International Organization | United States of America |
|---|---|
| Paper Number | TH/P6-25 |
Primary author
Dr
Xianzhu Tang
(Los Alamos National Laboratory)
Co-author
Zehua Guo
(Los Alamos National Laboratory)
