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Title: On the particle fluxes and density profiles in helical systems

Abstract

Quasilinear and neoclassical particle fluxes and their relation to the density profiles in helical plasmas are discussed, by taking the Large Helical Device (LHD) [O. Motojima et al., Nucl. Fusion 43, 1674 (2003)] as a representative example. Various magnetic configurations can be realized in the LHD experiments by changing the coil currents. The neoclassical particle flux shows strong configuration dependence through the significant change of effective helical ripple, while it is insensitive to the change of density profiles. On the other hand, the quasilinear flux shows weak dependence on the magnetic configurations while it strongly depends on the density profiles. As a result of the particle balance in the steady state in the no-source region, a qualitative explanation for the hollow density profiles, which are often observed experimentally in LHD, is proposed. In the appendixes, properties of quasilinear particle flux in a simple model tokamak are discussed, and expressions for neoclassical fluxes in the 1/{nu} regime in a coordinate system are given.

Authors:
; ; ;  [1]
  1. National Institute for Fusion Science, Toki, Gifu, 509-5292 (Japan)
Publication Date:
OSTI Identifier:
20960104
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 14; Journal Issue: 1; Other Information: DOI: 10.1063/1.2434796; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; CONFIGURATION; LHD DEVICE; NEOCLASSICAL TRANSPORT THEORY; PLASMA; PLASMA CONFINEMENT; PLASMA DENSITY; SPACE DEPENDENCE; STEADY-STATE CONDITIONS; STELLARATORS; TOKAMAK DEVICES

Citation Formats

Yamagishi, Osamu, Yokoyama, Masayuki, Nakajima, Noriyoshi, and Tanaka, Kenji. On the particle fluxes and density profiles in helical systems. United States: N. p., 2007. Web. doi:10.1063/1.2434796.
Yamagishi, Osamu, Yokoyama, Masayuki, Nakajima, Noriyoshi, & Tanaka, Kenji. On the particle fluxes and density profiles in helical systems. United States. doi:10.1063/1.2434796.
Yamagishi, Osamu, Yokoyama, Masayuki, Nakajima, Noriyoshi, and Tanaka, Kenji. Mon . "On the particle fluxes and density profiles in helical systems". United States. doi:10.1063/1.2434796.
@article{osti_20960104,
title = {On the particle fluxes and density profiles in helical systems},
author = {Yamagishi, Osamu and Yokoyama, Masayuki and Nakajima, Noriyoshi and Tanaka, Kenji},
abstractNote = {Quasilinear and neoclassical particle fluxes and their relation to the density profiles in helical plasmas are discussed, by taking the Large Helical Device (LHD) [O. Motojima et al., Nucl. Fusion 43, 1674 (2003)] as a representative example. Various magnetic configurations can be realized in the LHD experiments by changing the coil currents. The neoclassical particle flux shows strong configuration dependence through the significant change of effective helical ripple, while it is insensitive to the change of density profiles. On the other hand, the quasilinear flux shows weak dependence on the magnetic configurations while it strongly depends on the density profiles. As a result of the particle balance in the steady state in the no-source region, a qualitative explanation for the hollow density profiles, which are often observed experimentally in LHD, is proposed. In the appendixes, properties of quasilinear particle flux in a simple model tokamak are discussed, and expressions for neoclassical fluxes in the 1/{nu} regime in a coordinate system are given.},
doi = {10.1063/1.2434796},
journal = {Physics of Plasmas},
number = 1,
volume = 14,
place = {United States},
year = {Mon Jan 15 00:00:00 EST 2007},
month = {Mon Jan 15 00:00:00 EST 2007}
}
  • We report here on the application of an ultrashort-pulse reflectometer (USPR) to Large Helical Device in National Institute for Fusion Science. An impulse with picosecond pulse width is used as a source in an USPR. Since the bandwidth of a source is inversely related to the pulse width, we can utilize the frequency range of microwave to millimeter-wave by using wide band transmission lines. The density profiles can be reconstructed by collecting time-of-flight signal of each frequency component of an impulse reflected from each cutoff layer. Remote control system using super science information network has been introduced to the presentmore » USPR system.« less
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