Update of control system for auxiliary pumping and primary water cooling facilities
in JT-60 NBI http://jolissrch-inter.tokai-sc.jaea.go.jp/pdfdata/JAEA-Technology-2008-034.pdf by Kikuchi, Katsumi; Akino, Noboru; Ebisawa, Noboru; Ikeda, Yoshitaka; Takenouchi, Tadashi;
Tanai, Yutaka (Japan Atomic Energy Agency, Fusion Research and Development Directorate,
Naka, Ibaraki (Japan)); Seki, Norikazu (Nippon Advanced Technology, Co., Ltd., Tokai,
Ibaraki (Japan)); Japan Atomic Energy Agency, Tokai, Ibaraki (Japan) Read MoreCollapse
[en]
The control system for auxiliary pumping facility and primary water cooling facility
in JT-60 NBI was updated. To realize the cost reduction, the control system with many
input and outputs of 2000 was updated by JAEA itself using commercial Programmable
Logic Controllers (PLC's). JAEA also made software with 3600 ladder lines by JAEA
itself based on commercial basic program. In addition to the simple replacement of
the hardware and software, the function of remote operation has been newly added.
At present, the auxiliary pumping facility and the primary water cooling facility
have been stably operated without troubles. The remote operation enables to collect
the detailed information on the trouble more easily, resulting in a quick countermeasure
for the trouble. (author)$$$$
Recent results relevant to ignition physics and machine design issues 152 KB - http://www.iaea.org/inis/collection/NCLCollectionStore/_Public/31/011/31011468.pdf - Text Version by Coppi, B. (Massachusetts Institute of Technology, Cambridge, MA (United States); ENEA
Direction, Rome (Italy)); Airoldi, A. (Istituto di Fisica del Plasma - CNR, Milano
(Italy)); Bombarda, F. (Associazione Euratom-ENEA sulla Fusione, Frascati (Italy))
(and others); Ignitor Project Group fromFusion energy 1998. Proceedings. V. 1-4 Read MoreCollapse
[en]
The plasma regimes under which ignition can be achieved involve a characteristic range
of parameters and issues on which information has been provided by recent experiments.
In particular, these results have motivated a new, in-depth analysis of the expected
performance of the Ignitor machine as well as of the plasma processes that it can
investigate. The main results and recent advances in the design of key systems of
the machine are reported. (author)$$$$
The collisionless distortion of the ion (electron) distribution function at certain
points on a magnetic surface is studied in the framework of a simple model of a large
aspect ratio tokamak plasma. The flow velocity driven by this distortion is calculated.
The possibility of an additional non-uniform collisionless parallel current density
on a magnetic surface, other than the known neo-classical non-uniformity is shown.
The difference between the parallel current density on the low and high field side
of a magnetic surface is close to the neoclassical bootstrap current density. The
first Tore-Supra experimental test indicates the possibility of the poloidal non-uniformity
of the parallel current density. (authors)$$$$
One of the most important difficulties of numerical simulation of magnetized plasmas
is the existence of multiple time and space scales, which can be very different. In
order to produce good simulations of these multi-scale phenomena, it is recommended
to develop some models and numerical methods which are adapted to these problems.
Nowadays, the two-scale convergence theory introduced by G. Nguetseng and G. Allaire
is one of the tools which can be used to rigorously derive multi-scale limits and
to obtain new limit models which can be discretized with a usual numerical method:
this procedure is so-called a two-scale numerical method. The purpose of this thesis
is to develop a two-scale semi-Lagrangian method and to apply it on a gyrokinetic
Vlasov-like model in order to simulate a plasma submitted to a large external magnetic
field. However, the physical phenomena we have to simulate are quite complex and there
are many questions without answers about the behaviour of a two-scale numerical method,
especially when such a method is applied on a nonlinear model. In a first part, we
develop a two-scale finite volume method and we apply it on the weakly compressible
1D isentropic Euler equations. Even if this mathematical context is far from a Vlasov-like
model, it is a relatively simple framework in order to study the behaviour of a two-scale
numerical method in front of a nonlinear model. In a second part, we develop a two-scale
semi-Lagrangian method for the two-scale model developed by E. Frenod, F. Salvarani
et E. Sonnendrucker in order to simulate axisymmetric charged particle beams. Even
if the studied physical phenomena are quite different from magnetic fusion experiments,
the mathematical context of the one-dimensional paraxial Vlasov-Poisson model is very
simple for establishing the basis of a two-scale semi-Lagrangian method. In a third
part, we use the two-scale convergence theory in order to improve M. Bostan's weak-*
convergence results about the finite Larmor radius model, and we develop a forward
semi-Lagrangian method in order to validate these theoretical results. (author)$$$$
The detailed project for developing Large Area Neutron Scintillation Detector Array
(LaNSA) to be used for measuring fusion fuel area density on Shenguang III prototype
is presented, including experimental principle, detector working principle, electronics
system design and the needs for target chamber etc. The detailed parameters for parts
are given and the main causes affecting the system function are analyzed. The realization
path is introduced. (authors)$$$$
Analysis program for magnetic field, inductance of air-core coils: COIL 2 MB - http://www.iaea.org/inis/collection/NCLCollectionStore/_Public/36/116/36116769.pdf - Text Version by Yoshida, Kiyoshi; Isono, Takaaki; Sugimoto, Makoto; Okuno, Kiyoshi (Japan Atomic Energy
Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment); Japan Atomic Energy Research Inst., Kashiwa, Chiba (Japan) Read MoreCollapse
[en]
In case of designing a superconducting coil, one must calculate a magnetic field and
its inductance many times in order to arrange proper design parameters of a superconducting
coil because there are many design parameters to evaluate. A superconducting coil
cannot be designed by the optimum condition if a magnetic field and inductance cannot
be computed easily. When a superconducting coil is actually energized, measurement
values of the static magnetic field and its inductance are very well agreed with calculated
values. The static magnetic field and inductance of the coil that does not contain
a ferromagnetic material can be precisely calculated by using the numerical integration.
The analytic method were developed and established in 1970's. This paper shows the
calculation program COIL that has been developed by applying this analytic method
by the superconducting magnet laboratory in JAERI. The program COIL is qualified by
the comparison between measured and calculated values of the magnetic field and its
inductance in case of several real superconducting coils. The program COIL is specified
to analyze superconducting coils in a tokamak device. The magnetic field that is created
from those coils, and self and mutual inductance can be easily computed by using the
program COIL. Even for a complicated tokamak device, the magnetic field and inductance
can be calculated in several minutes by using the recent the high performance personal
computer. The program COIL contributes to design the superconducting coils for ITER
and others. (author)$$$$
The goal of magnetic fusion research is to extract the power released by fusion reactions
and carried by the product of these reactions, liberated at energies of the order
of a few MeV. The feasibility of fusion energy production relies on our ability to
confine these energetic particles, while keeping the thermonuclear plasma in safe
operating conditions. For that purpose, it is necessary to understand and find ways
to control the interaction between energetic particles and the thermonuclear plasma.
Reaching these two goals is the general motivation for this work. More specifically,
our focus is on one type of instability, the Beta Alfven Eigenmode (BAE), which can
be driven by energetic particles and impact on the confinement of both energetic and
thermal particles. In this work, we study the characteristics of BAEs analytically
and derive its dispersion relation and structure. Next, we analyze the linear stability
of the mode in the presence of energetic particles. First, a purely linear description
is used, which makes possible to get an analytical linear criterion for BAE destabilization
in the presence of energetic particles. This criterion is compared with experiments
conducted in the Tore-Supra tokamak. Secondly, because the linear analysis reveals
some features of the BAE stability which are subject to a strong nonlinear modification,
the question is raised of the possibility of a sub-critical activity of the mode.
We propose a simple scenario which makes possible the existence of meta-stable modes,
verified analytically and numerically. Such a scenario is found to be relevant to
the physics and scales characterizing BAEs. (author)$$$$
Geodesic acoustic mode(GAM) driven by energetic particles are observed in the Large
Helical Device by a heavy ion beam probe. The GAM frequency shifts upward in plasmas
with monotonic magnetic shear. In plasmas with reversed magnetic shear, on the other
hand, the observed GAM and the energetic-particle induced mode, which is probably
reversed-shear induced Alfven Eigenmode(RSAE), appears, and the GAM frequency becomes
constant. The GAM in the reversed-shear plasma localizes near the magnetic axis. It
is confirmed that the energetic-particle induced GAM is accompanied by the electrostatic
potential fluctuation and the radial electric field fluctuation. The amplitude of
the potential fluctuation is several hundred volts, and it is much larger than the
potential fluctuation associated with turbulence-induced GAMs observed in the edge
region in tokamak plasmas. The energetic-particle induced GAM modulates the amplitude
of the ambient density fluctuation at the GAM frequency. (author)$$$$
Predictions of alpha heating in L-mode and H-mode DT plasmas in ITER are generated
using the PTRANSP code. The baseline toroidal field of 5.3 T, plasma current ramped
to 15 MA and a flat electron density profile ramped to Greenwald fraction 0.85 are
assumed. Various combinations of external heating by negative ion neutral beam injection,
ion cyclotron resonance, and electron cyclotron resonance are assumed to start half-way
up the density ramp. The time evolution of plasma temperatures and, for some cases,
toroidal rotation are predicted assuming GLF23 and boundary parameters. Significant
toroidal rotation and flow-shearing rates are predicted by GLF23 even in the L-mode
phase with low boundary temperatures, and the alpha heating power is predicted to
be significant if the power threshold for the transition to H-mode is higher than
the planned total heating power. The alpha heating is predicted to be 8-76 MW in L-mode
at full density. External heating mixes with higher beam injection power have higher
alpha heating power. Alternatively if the toroidal rotation is predicted assuming
that the ratio of the momentum to thermal ion energy conductivity is 0.5, the flow-shearing
rate is predicted to have insignificant effects on the GLF23- predicted temperatures,
and alpha heating is predicted to be 8-20 MW. In H-mode plasmas the alpha heating
is predicted to depend sensitively on the assumed pedestal temperatures. Cases with
fusion gain greater than 10 are predicted to have alpha heating greater than 80 MW.$$$$