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Sherwood 2015 Abstracts Abstract Details
| status: | file name: | submitted: | by: |
|---|---|---|---|
| approved | espinosa_sherwood15.pdf | 2015-04-01 14:45:52 | Silvia Espinosa |
IMPURITY DENSITY AND TEMPERATURE ASYMMETRY AND FLOW IN TOKAMAK PEDESTALS
Author: Silvia Espinosa
Requested Type: Poster Only
Submitted: 2015-01-12 12:52:25
Co-authors: Peter J. Catto
Contact Info:
MIT,PSFC
77 Massachusetts Ave, NW16
Cambridge, Massachuse 02139
United States
Abstract Text:
A high confinement mode pedestal has density and potential variation on the poloidal ion gyroradius scale, making alternate neoclassical descriptions necessary [1]. Alcator C-Mod experiments [2] make it clear that the impurity diamagnetic drift contribution must be allowed to be comparable to the impurity poloidal and toroidal flows to measure the radial electric field. In addition, a substantial poloidal asymmetry in impurity temperature is noticed. Furthermore, Churchill et al.[3] experimentally observe stronger poloidal variation of the impurity density than predicted by the most comprehensive theoretical models developed to date [4]. Our research formulates a neoclassical ordering, valid for slowly varying background ion temperature profiles in subsonic ion pedestals, that allows impurity diamagnetic flow effects to enter to lowest order. Importantly, the impurity flow must be allowed to reach sonic speeds. It results in significant and strong poloidal impurity temperature and density variation, respectively; possibly providing a more realistic model for pedestal observations.
[1] G.Kagan et al.,Plasma Phys Contr F 50,08501
[2] C.Theiler et al.,Nucl Fusion 54,083017
[3] R.M.Churchill et al.,Nucl Fusion 53,122002
[4] P.Helander,Phys Plasmas 5,3999
Supported by DOE Grant DE-FG0291ER54109 and La Caixa Fellowship.
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