Speaker
Luis F. Delgado-Aparicio
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P4.1103.pdf
Rotation-induced electrostatic-potentials and density asymmetries in NSTX
L. F. Delgado-Aparicio1, R. E. Bell1, G. J. Kramer1, M. Podestà1,
B. P. LeBlanc1, A. Diallo1, S. Gerhardt1 and M. Ono1
1
Princeton Plasma Physics Laboratory, Princeton, NJ, 08540, USA
The computation of rotation-induced electrostatic potentials is currently being used to study
the associated two-dimensional distribution of impurity density asymmetries in NSTX and
NSTX-U plasmas. This calculation relies
on flux-surface quantities like electron
and ion temperature (Te,i) and rotation
frequency (ωφ) and finds the 2D
electron, deuterium and carbon density
profiles self-consistently assuming the
presence of a poloidal variation due to
centrifugal forces. The iterative solution
[1] for the electrostatic potential
difference [Δϕ = ϕ(θ) - ϕ(θ =0)] are
routinely obtained and compared with
the values derived from the ideal
solution to quasi-neutrality, which
assumes that the main low-Z intrinsic
impurity (e.g. carbon) is in the trace
limit. An ad-hoc solution, which
attempts to extend the ideal
Fig. 1. Rotation-induced potential and overall effect in
approximation beyond the trace limit [2], NSTX
does not adequately captures the physics of finite mass and Zeff. Nevertheless, the net-change
of the plasma potential profile due to the presence of the rotation-induced electrostatic well is
smaller than 6%. This calculation also finds 2D asymmetries for medium- to high-Z impurity
density profiles that are at the trace limit with very small changes to quasi-neutrality and Zeff.
While the asymmetry in the core radiated power density from low-Z ions (e.g. D, C, O, Ne) is
relatively small, the core density and radiation from medium- to high-Z’s (e.g. Ar, Fe, Mo, W)
will be strongly affected by centrifugal forces. This work is supported by the U.S. Department
of Energy, Office of Fusion Energy Sciences under contract number DE-AC02-09CH11466.
[1] E. Belli and J. Candy, PPCF, 51, 075018, (2009).
[2] T. Odstrcil, at al., PPCF, 60, 014003, (2018).
