Title
Rotation-induced electrostatic-potential and its effect on the radial electric field, impurity density and radiated power asymmetries in NSTX
Date Issued
01 January 2018
Access level
metadata only access
Resource Type
conference paper
Author(s)
Bell R.E.
Kramer G.J.
Podest M.
LeBlanc B.P.
Diallo A.
Stratton B.
Paul S.
Kaye S.
Gerhardt S.
Menard J.
Yamazaki H.
Takase Y.
Ono M.
Princeton University
Publisher(s)
European Physical Society (EPS)
Start page
1300
End page
1303
Volume
2018-July
Language
English
OCDE Knowledge area
Física de plasmas y fluídos
Scopus EID
2-s2.0-85057206905
ISBN of the container
978-151086844-1
Conference
45th EPS Conference on Plasma Physics, EPS 2018
Sponsor(s)
in NSTX and NSTX-U. This calculation also finds 2D asymmetry factors (see Fig 6) for impurity profiles which are at the trace limit with very small changes to quasi- neutrality and Zeff. Estimates of average charge state and radiated power density (Prad) can be made using coronal equilibrium. While the asymmetry in the core radiated power from low-Z ions (e.g. D, C, O, Ne) is relatively small, the core density and radiation from medium-to high-Z’s will be strongly affected by centrifugal forces (see 2D Prad profiles in Fig 7). At even higher toroidal rotation, the asymmetry is stronger concentrating the Fe, Mo and W dratead powi er strictly to theol-fiewld-side. In summary, the computation of rotation-induced electrostatic potentials is being used to study the associated two-dimensional distribution of impurity density asymmetries in NSTX. This calculation relies on flux-surface quantities like Te, Ti and ωφ. The iterative process finds the 2D density profiles and the electrostatic Fig. 6. Mass-dependence of asymmetry potentials (Δϕ) self-consistently assuming poloidal variation due to centrifugal forces. The depth of the potential well can reach -110 to -280 V for core NSTX rotation between 180 – 360 km/s but remains very small if one compares with the core plasma potential or the energy of fast ions. The net-change of the plasma potential and radial electric field is of the order of just 5-6% and in accordance with a simple theoretical calculation. This computation is being used to increase our understanding of asymmetries and the reduction of Z-peaking, to examine the effect of electrostatic potentials possibly changing the heat and particle transport, radiation asymmetries before tearing mode onsets, as well as to aid the design of new diagnostics for NSTX-U (e.g. ME-SXR [9], XICS, Bolometers, etc). This work is supported by the U.S. Department of Energy, Office of uFion Esnergy Sciences under contract number DE-AC02-09CH11466.
Sources of information:
Directorio de Producción Científica
Scopus