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3D Equilibrium Effects Due to RMP Application on DIII-D

Description: The mitigation and suppression of edge localized modes (ELMs) through application of resonant magnetic perturbations (RMPs) in Tokamak plasmas is a well documented phenomenon [1]. Vacuum calculations suggest the formation of edge islands and stochastic regions when RMPs are applied to the axisymmetric equilibria. Self-consistent calculations of the plasma equilibrium with the VMEC [2] and SPEC [3] codes have been performed for an up-down symmetric shot (142603) in DIII-D. In these codes, a self… more
Date: June 20, 2012
Creator: Lazerson, S.; Lazarus, E.; Hudson, S.; Pablant, N. & Gates, D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

3D Equilibrium Effects Due to RMP Application on DIII-D

Description: The mitigation and suppression of edge localized modes (ELMs) through application of resonant magnetic perturbations (RMPs) in Tokamak plasmas is a well documented phenomenon. Vacuum calculations suggest the formation of edge islands and stochastic regions when RMPs are applied to the axisymmetric equilibria. Self-consistent calculations of the plasma equilibrium with the VMEC and SPEC codes have been performed for an up-down symmetric shot in DIII-D. In these codes, a self-consistent calculati… more
Date: June 20, 2012
Creator: Lazerson, S.; Lazarus, E.; Hudson, S.; Pablant, N. & Gates, D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Atomic Models for Motional Stark Effects Diagnostics

Description: We present detailed atomic physics models for motional Stark effects (MSE) diagnostic on magnetic fusion devices. Excitation and ionization cross sections of the hydrogen or deuterium beam traveling in a magnetic field in collisions with electrons, ions, and neutral gas are calculated in the first Born approximation. The density matrices and polarization states of individual Stark-Zeeman components of the Balmer {alpha} line are obtained for both beam into plasma and beam into gas models. A det… more
Date: July 26, 2007
Creator: Gu, M F; Holcomb, C; Jayakuma, J; Allen, S; Pablant, N A & Burrell, K
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Optimization of the Configuration of Pixilated Detectors Based on the Shannon-Nyquist Theory for the X-Ray Spectroscopy of Hot Tokamak Plasmas

Description: This paper describes an optimization of the detector configuration, based on the Shannon-Nyquist theory, for two major x-ray diagnostic systems on tokamaks and stellarators: x-ray imaging crystal spectrometers and x-ray pinhole cameras. Typically, the spectral data recorded with pixilated detectors are oversampled, meaning that the same spectral information could be obtained using fewer pixels. Using experimental data from Alcator C-Mod, we quantify the degree of oversampling and propose altern… more
Date: June 13, 2012
Creator: Wang, E.; Beiersdorfer, P.; Bitter, M.; Delgado-Aprico; Hill, K. W. & Pablant, N.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Application of Spatially Resolved High Resolution Crystal Spectrometry to ICF Plasmas

Description: High resolution (λ/Δ#3;λ ~ 10 000) 1D imaging x-ray spectroscopy using a spherically bent crystal and a 2D hybrid pixel array detector is used world wide for Doppler measurements of ion-temperature and plasma flow-velocity profiles in magnetic confinement fusion plasmas. Meter sized plasmas are diagnosed with cm spatial resolution and 10 ms time resolution. This concept can also be used as a diagnostic of small sources, such as inertial confinement fusion plasmas and targets on x-ray light sour… more
Date: September 15, 2012
Creator: Hill, Kenneth W.; Bitter, M.; Delgado-Aprico, L.; Pablant, N. A.; Beirersdorfer, P.; Schneider, M. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

A New Scheme for Stigmatic X-ray Imaging with Large Magnification

Description: This paper describes a new x-ray scheme for stigmatic imaging. The scheme consists of one convex spherically bent crystal and one concave spherically bent crystal. The radii of curvature and Bragg reflecting lattice planes of the two crystals are properly matched to eliminate the astigmatism, so that the conditions for stigmatic imaging are met for a particular wavelength. The magnification is adjustable and solely a function of the two Bragg angles or angles of incidence. Although the choice o… more
Date: August 8, 2012
Creator: Bitter, M.; Delgado-Aprico, L. F.; Pablant, N. A.; Scott, S.; Jones, F.; Beiersdorfer, P. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Layout And Results From The Initial Opeeration Of The High-resolution X-ray Imaging Crystal Spectrometer On The Large Helical Device

Description: First results of ion and electron temperature pro le measurements from the x-ray imaging crystal spectrometer (XICS) diagnostic on the Large Helical Device (LHD) are presented. This diagnostic system has been operational since the beginning of the 2011 LHD experimental campaign and is the rst application of the XICS diagnostic technique to helical plasma geometry. The XICS diagnostic provides measurements of ion and electron temperature pro les in LHD with a spatial resolution of 2cm and a time… more
Date: April 5, 2012
Creator: Pablant, N A; Delgado-Apricio, L; Goto, M; Hill, K W; Lzerson, S; Morita, S et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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