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Title: Short wavelength turbulence generated by shear in the quiescent H-mode edge on DIII–D [Short wavelength turbulence generated by shear in the QH-mode edge on DIII-D]

A region of turbulence with large radial wavenumber (k rρ s > 1) is found in the high-shear portion of the plasma edge in Quiescent H-mode (QH-mode) on DIII{D using the Phase Contrast Imaging (PCI) diagnostic. At its peak outside the minimum of the E r well, the turbulence exhibits large amplitude $$\tilde{n}$$/n ~ 40%, with large radial wavenumber |$$\bar{k}$$ r/ $$\bar{k}$$ θ| ~ 11 and short radial correlation length L ri ~ 0.2. The turbulence inside the E r well minimum is characterized by the opposite sign in radial wavenumber from that of turbulence outside the minimum, consistent with the expected effects of velocity shear. The PCI diagnostic provides a line-integrated measurement of density uctuations, so data is taken during a scan of plasma position at constant parameters to allow the PCI to sample a range in k r/k θ . Analysis of the Doppler Shift and plasma geometry allows the turbulence to be localized to a narrow region 3 mm inside the last closed flux surface (LCFS), outside the minimum of the E r well. The turbulence amplitude and radial wavenumber and correlation length are determined by fitting the PCI results with a simple non-isotropic turbulence model with two regions of turbulence. Finally, these PCI observations, made in QH-mode, are qualitatively similar to those made in standard ELM-free H-mode and between edge localized modes (ELMs), suggesting a similar role for large k r turbulence there.
Authors:
 [1] ;  [1] ;  [1] ;  [2]
  1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
  2. General Atomics, San Diego, CA (United States)
Publication Date:
Grant/Contract Number:
FC02-04ER54698
Type:
Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 21; Journal Issue: 6; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Research Org:
Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
Sponsoring Org:
USDOE Office of Nuclear Energy (NE)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY
OSTI Identifier:
1354815

Rost, Jon C., Porkolab, Miklos, Dorris, James R., and Burrell, Keith H.. Short wavelength turbulence generated by shear in the quiescent H-mode edge on DIII–D [Short wavelength turbulence generated by shear in the QH-mode edge on DIII-D]. United States: N. p., Web. doi:10.1063/1.4883135.
Rost, Jon C., Porkolab, Miklos, Dorris, James R., & Burrell, Keith H.. Short wavelength turbulence generated by shear in the quiescent H-mode edge on DIII–D [Short wavelength turbulence generated by shear in the QH-mode edge on DIII-D]. United States. doi:10.1063/1.4883135.
Rost, Jon C., Porkolab, Miklos, Dorris, James R., and Burrell, Keith H.. 2014. "Short wavelength turbulence generated by shear in the quiescent H-mode edge on DIII–D [Short wavelength turbulence generated by shear in the QH-mode edge on DIII-D]". United States. doi:10.1063/1.4883135. https://www.osti.gov/servlets/purl/1354815.
@article{osti_1354815,
title = {Short wavelength turbulence generated by shear in the quiescent H-mode edge on DIII–D [Short wavelength turbulence generated by shear in the QH-mode edge on DIII-D]},
author = {Rost, Jon C. and Porkolab, Miklos and Dorris, James R. and Burrell, Keith H.},
abstractNote = {A region of turbulence with large radial wavenumber (krρs > 1) is found in the high-shear portion of the plasma edge in Quiescent H-mode (QH-mode) on DIII{D using the Phase Contrast Imaging (PCI) diagnostic. At its peak outside the minimum of the Er well, the turbulence exhibits large amplitude $\tilde{n}$/n ~ 40%, with large radial wavenumber |$\bar{k}$r/ $\bar{k}$θ| ~ 11 and short radial correlation length Lr/ρ i ~ 0.2. The turbulence inside the Er well minimum is characterized by the opposite sign in radial wavenumber from that of turbulence outside the minimum, consistent with the expected effects of velocity shear. The PCI diagnostic provides a line-integrated measurement of density uctuations, so data is taken during a scan of plasma position at constant parameters to allow the PCI to sample a range in kr/kθ . Analysis of the Doppler Shift and plasma geometry allows the turbulence to be localized to a narrow region 3 mm inside the last closed flux surface (LCFS), outside the minimum of the Er well. The turbulence amplitude and radial wavenumber and correlation length are determined by fitting the PCI results with a simple non-isotropic turbulence model with two regions of turbulence. Finally, these PCI observations, made in QH-mode, are qualitatively similar to those made in standard ELM-free H-mode and between edge localized modes (ELMs), suggesting a similar role for large kr turbulence there.},
doi = {10.1063/1.4883135},
journal = {Physics of Plasmas},
number = 6,
volume = 21,
place = {United States},
year = {2014},
month = {6}
}