Study on impurity hole plasmas by global neoclassical simulation

K Fujita, S Satake, M Nunami, JM García-Regaña… - Nuclear …, 2021 - iopscience.iop.org
An impurity hole observed in the large helical device (LHD) is a hollow density profile of an
impurity ion species formed in the core plasma where the negative (inward-pointing) …

3D toroidal physics: Testing the boundaries of symmetry breaking

DA Spong - Physics of Plasmas, 2015 - pubs.aip.org
Toroidal symmetry is an important concept for plasma confinement; it allows the existence of
nested flux surface MHD equilibria and conserved invariants for particle motion. However …

Measurements of radial profile of hydrogen and deuterium density in isotope mixture plasmas using bulk charge exchange spectroscopy

K Ida, M Yoshinuma, K Yamasaki… - Review of Scientific …, 2019 - pubs.aip.org
A bulk charge exchange spectroscopy system has been applied to measure the radial
profiles of the hydrogen (H) and deuterium (D) density ratio in the isotope mixture plasma in …

Collisionality dependence and ion species effects on heat transport in He and H plasma, and the role of ion scale turbulence in LHD

K Tanaka, K Nagaoka, S Murakami, H Takahashi… - Nuclear …, 2017 - iopscience.iop.org
Surveys of the ion and electron heat transports of neutral beam (NB) heating plasma were
carried out by power balance analysis in He and H rich plasma at LHD. Collisionality was …

Strong suppression of impurity accumulation in steady-state hydrogen discharges with high power NBI heating on LHD

Y Nakamura, N Tamura, M Yoshinuma, C Suzuki… - Nuclear …, 2017 - iopscience.iop.org
Strong suppression of impurity accumulation is observed in long pulse hydrogen discharges
with high power NBI (neutral beam injection) heating (P nbi> 10 MW) on the large helical …

The internal disruption as hard Magnetohydrodynamic limit of 1/2 sawtooth like activity in large helical device

J Varela, KY Watanabe, S Ohdachi - Physics of Plasmas, 2012 - pubs.aip.org
Large helical device (LHD) inward-shifted configurations are unstable to resistive MHD
pressure-gradient-driven modes. Sawtooth like activity was observed during LHD operation …

Impacts of external momentum torque on impurity particle transport in LHD

M Nunami, M Sato, M Nakata, S Toda… - Plasma and Fusion …, 2017 - jstage.jst.go.jp
Particle transport processes of impurity ions in a multi-ion-species plasma in the Large
Helical Device are investigated by neoclassical transport simulations. While the quasi-linear …

Hard magnetohydrodynamic limit in 1/3 sawtooth like activity in LHD

J Varela, KY Watanabe, S Ohdachi, Y Narushima - Physics of Plasmas, 2014 - pubs.aip.org
The optimization of LHD discharges in inward-shifted configurations with 1/3 sawtooth like
activity is an open issue. These relaxation events limit the LHD performance driving a …

Role of neoclassical transport and radial electric field in LHD plasmas

M Yokoyama, A Wakasa, S Murakami… - Fusion Science and …, 2010 - Taylor & Francis
This paper reviews how neoclassical (NC) transport analyses have been exploited to
predict/understand the improved confinement achieved in the Large Helical Device (LHD) …

Causal impact of magnetic fluctuations in slow and fast L–H transitions at TJ-II

BP van Milligen, T Estrada, BA Carreras… - Physics of …, 2016 - pubs.aip.org
B. Ph. van Milligen, T. Estrada, BA Carreras, E. Ascasíbar, C. Hidalgo, I. Pastor, JM
Fontdecaba, R. Balbín, TJ-II Team; Causal impact of magnetic fluctuations in slow and fast L …