Dr
TAKESHI IDO
(National Institute for Fusion Science)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
Abrupt excitation of a geodesic acoustic mode (GAM) has been observed in the Large Helical Device (LHD), when the frequency of an up-chirping energetic-particle driven GAM (EGAM) approaches twice the ordinary GAM frequency. The abruptly exited GAM has larger amplitude and a lower frequency than the initially excited EGAM. The amplitude dependence of the growth rate of the abrupt GAM indicates...
Dr
Alfredo Portone
(Fusion For Energy)
21/10/2016, 14:00
THS - Magnetic Confinement Theory and Modelling: Stability
Poster
In the design of next step tokamak devices, it will be of key importance to carefully optimize the plasma magnetic configuration, in particular its elongation, triangularity and aspect ratio. Indeed, the sharp dependence of the safety factor q upon plasma elongation and, as a consequence, of the maximum achievable plasma current in disruption-free operation mode is of paramount importance to...
Dr
Naoyuki Fukumoto
(University of Hyogo)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
Compact toroid (CT) injection was conducted on several middle-class tokamaks in the previous experiments for development of an advance fueling method. We have carried out CT injection in a Spherical Tokamak (ST) plasma, for the first time, on QUEST equivalent to the tokamaks in facility size. The primary aim of the experiment is to produce a high-density ST plasma and control its density...
Dr
Joerg Stober
(IPP Garching)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
Since 2007 the tokamak ASDEX Upgrade (AUG) successfully operates with fully W-coated
plasma facing components. Operation in this environment is facilitated using high levels of
deuterium puff to minimize W erosion of the out-board limiters by ELMs and by seeding impurities
in order to control divertor temperature at a low level to protect especially the W-coatings
of graphite tiles. These...
Dr
Tatsuya Kobayashi
(National Institute for Fusion Science)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
Recent studies have indicated that the local theory of the electron heat transport cannot model the plasma response against the modulation electron cyclotron resonance heating (MECH) correctly. In this paper we propose a new method to analyze the MECH experiment, aiming to examine the local transport model. The method is applied to the MECH experiments performed in the helical (LHD and TJ- II)...
Dr
Daniele Carnevale
(Universita' Roma Tor Vergata, Dipartimento di Ing. Civile ed Ing. Informatica)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
The challenging task for a disruption mitigation system (DMS) is the implementation of reliable strategies in order to mitigate thermal, mechanical and electromagnetic loads at disruptions. Furthermore, the DMS has to cope with control and suppression of runaway electron beams, which are possibly generated during major disruptions, in order to avoid localized high-energy deposition causing...
Prof.
Boris Breizman
(The University of Texas at Austin)
21/10/2016, 14:00
THC - Magnetic Confinement Theory and Modelling: Confinement
Poster
When plasmas have a sufficient number of energetic particles to induce instability, such as may occur in burning plasmas, it is important to have a reliable method of predicting the nature of the unstable state that will arise. Two extreme scenarios for the TAE frequency, $\omega_{TAE}$ arises: relatively steady oscillations at one extreme and chirping oscillations at the other extreme. For...
Prof.
Rajesh Srivastava
(Indian Institute of Technology (I.I.T.) Roorkee, India)
21/10/2016, 14:00
FIP - Fusion Engineering, Integration and Power Plant Design
Poster
An improved collisional radiative (CR) model has been developed for hydrogen-cesium plasma for its application to the negative hydrogen ion sources where we used reliable cross sections. The required electron impact excitation cross-sections have been obtained using fully relativistic distorted wave theory for various fine-structure transitions from the ground as well as excited states. These...
Mr
Vladimir Kornev
(Ioffe Institute)
21/10/2016, 14:00
EXW - Magnetic Confinement Experiments: Wave–plasma interactions; current drive; heating; energetic particles
Poster
Recent experiments on the TUMAN-3M compact tokamak were aimed at study of fast ion (FI) capture and confinement in co-current NBI heating scheme. Target plasma parameters in the experiments were as follows: R0 = 0.53 m, al = 0.22 m, BT ≤ 1 T, Ip ≤ 180 kA, ne ≤ 4•1019 m-3, Te(0) ≤0.7 keV, Ti ≤ 0.2 keV. Maximum output power of deuterium neutral beam Pinj = 700 kW. Measurement of 2.45 MeV DD...
Dr
Takuya Goto
(National Institute for Fusion Science)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
In a heliotron type system like LHD, compatibility between MHD stability and good confinement is recognized as one of the crucial issues. This paper reports the world’s first attempt of the close investigation of self-consistent solution of plasma operation scenario in view of MHD stability, anomalous transport, alpha energy loss and impurity effect in addition to MHD equilibrium and...
Prof.
Aleksandr Burdakov
(Budker Institute of Nuclear Physics)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
In 2015, the existing GOL-3 multiple-mirror trap has been converted into three specialized devices, each dedicated to a specific scientific problem. Experiments on studies of plasma mechanisms of sub-THz radiation generation use the GOL-3T device. A device with a sub-ms electron beam was isolated for further studies of ITER-grade transient heat loads to tungsten. Research of multiple-mirror...
Mr
David DOUAI
(CEA, IRFM, Association Euratom-CEA, 13108 St Paul lez Durance, France)
21/10/2016, 14:00
EXD - Magnetic Confinement Experiments: Plasma–material interactions; divertors; limiters; scrape-off layer (SOL)
Poster
Wall conditioning will be required in JT-60SA to control fuel and impurity recycling and to improve plasma performance and reproducibility. In addition to glow discharge cleaning, operable only in the absence of toroidal field, Electron Cyclotron Wall Conditioning (ECWC) plasmas created with its ECRF launchers are envisioned. ECWC has been successfully operated in Helium at the first harmonic...
Dr
Petr Savrukhin
(NRC Kurchatov Institute)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
Experiments in the T-10 tokamak (R=1.5m, a=0.3m) have demonstrated possibility of control of the plasma current decay and prevention of formation of the non-thermal (Eg>150keV) electron beams after an energy quench at the density limit disruption using electron cyclotron heating (ECRH) and pre-programmed Ohmic (OH) power supply system. Quasi-stable plasma operation with repetitive sawtooth...
Dr
Cristian Galperti
(Ecole Polytechnique Fédérale de Lausanne (EPFL), SPC, CH-1015 Lausanne, Switzerland)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
A key feature of the new digital plasma control system installed on the TCV tokamak is its possibility to rapidly design, test and deploy real-time algorithms. It accommodates hundreds of diagnostic inputs and actuator outputs, and offers the possibility to design advanced control algorithms with better knowledge of the plasma state and to coherently control all TCV actuators, including...
Dr
YURI IGITKHANOV
(KIT)
21/10/2016, 14:00
THD - Magnetic Confinement Theory and Modelling: Plasma–material interactions; divertors, limiters, SOL
Poster
One of the important tasks of the DEMO divertor design optimization is to ensure a desirable divertor performance and high pumping efficiency by varying, for example, the divertor dome height and pumping port position. In this paper we analyse the latest European DEMO divertor design with the pumping port located at the bottom of the divertor plenum. Optimization of the dome height and its...
Prof.
Michael Probst
(University of Innsbruck)
21/10/2016, 14:00
MPT - Materials Physics and Technology
Poster
Electron-impact cross sections yield the probability of an electron reacting with a particle – a molecule, an ion or an atom – as a function of the energy of that electron.
At low energies so-called dissociative electron attachment (DEA) is the predominant reaction mechanism.
At energies of the incoming electron higher than the ionization threshold of the particle, typically the particle...
Dr
Onofrio Tudisco
(ENEA)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
Here is reported the simulation of density evolution in discharges performed at Frascati Tokamak Upgrade (FTU) where a thermo-diffusion term have been used instead of the particle pinch. In these discharges a sensible density peaking is observed at high density, subsequent the formation of a strong MARFE thermal instability at plasma edge. They have been obtained in an experimental campaign...
Prof.
Byron Peterson
(National Institute for Fusion Science)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
Various noble gasses have been seeded in the Large Helical Device (LHD) to reduce the divertor heat load through enhanced radiation [1]. At the vertically elongated cross-section, in the case of N_2 seeding, bolometric images show additional outboard radiation, while in the case of Ne, only inboard radiation is observed. With N_2 seeding, radiation is observed by two imaging bolometers [2],...
Dr
Marco Wischmeier
(IPP Garching)
21/10/2016, 14:00
EXD - Magnetic Confinement Experiments: Plasma–material interactions; divertors; limiters; scrape-off layer (SOL)
Poster
Future fusion devices such as ITER and DEMO face a major challenge when limiting the thermal power load reaching the plasma-facing components, PFCs, to values below the engineering specifications. In the case of DEMO the combination of power load and erosion limitations require plasma operation at a high fraction of power dissipation, estimated to be well beyond 90%, while maintianing a...
Dr
Hiroyuki Okada
(Institute of Advanced Energy, Kyoto University)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
The fast ion generation and confinement are studied by using ICRF minority heating (H minority and D majority) for the simulation study of alpha particles, whose heating is essential for fusion reactors. In a three dimensional magnetic field device, Heliotron J (R_0 = 1.2 m, a = 0.1-0.2 m, B_0 1.5 T), fast ion generation and confinement by ICRF minority heating are studied in combination...
Mr
Basilio Esposito
(ENEA)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
Runaway mitigation is one of the main concerns for safe ITER operation. The disruption mitigation system, still under development for ITER, will be designed to inject the correct amount of high-Z impurities in order to dissipate thermal and magnetic energy by radiation within the mechanical limits of the structure. During the ITER disruption phase and specifically during the Current Quench...
Dr
Isabel Maria Ferreira Nunes
(IPFN/IST)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
The hydrogen campaign completed at JET in 2016 has demonstrated isotope ratio control in JET-ILW using gas puffing and pellets for fuelling, Neutral Beam Injection alone or in combination, with Dalpha/Halpha spectroscopy as a diagnostic. The plasma properties such as confinement, L-H threshold, density limit depend on the isotope composition. The L-H transition power increases with the...
Dr
Katsumi Ida
(National Institute for Fusion Science)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
Abrupt damping of toroidal flow associated with a transition from nested magnetic flux surface to a stochastic magnetic field is observed when the magnetic shear at the rational surface decreases to 0.5 in the Large Helical Device (LHD). 1) This flow damping and resulting profile flattening is much stronger than that expected from the Rechester-Rosenbluth model. 2) The stochastization starts...
Dr
Matthew John Hole
(Australian National University)
21/10/2016, 14:00
THC - Magnetic Confinement Theory and Modelling: Confinement
Poster
We highlight recent ANU-led research in energetic particle physics and multi-relaxed region MHD. Topics include (1) the inclusion of anisotropy and flow into tokamak equilibria, stability and wave-particle interaction studies, (2) the calculation of energetic geodesic acoustic modes (EGAMs) using fluid theory, (3) the development and implementation of continuum damping in 3D, (4) the...
Prof.
Michiaki Inomoto
(The University of Tokyo)
21/10/2016, 14:00
EXW - Magnetic Confinement Experiments: Wave–plasma interactions; current drive; heating; energetic particles
Poster
Spherical tokamak (ST) concept provides a potential for high-beta plasma confinement, however, it requires downsizing or removal of center solenoid (CS) coil because of restricted room in the central region. As one of candidates for CS-free start-up methods, combination of torus discharge by using external poloidal field coils and axial merging technique has been developed in the UTST...
Dr
Xianli Huang
(National Institute for Fusion Science)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
In the Large Helical Device (LHD), the n_e profile can exhibit a peaked, flat or hollow shape. For the purpose of heavy impurity control, it is important to investigate the effect of n_e profile on the impurity transport.
Radial emissions profiles of Fe^16+ through Fe^23+ ions have been simultaneously measured in the Fe L_α array. The total iron density (N_Fe(ρ)) profile is then calculated...
Dr
Gen Motojima
(National Institute for Fusion Science)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
We report the global particle balance analysis and its relationship with the plasma wall interaction emerging for the first time in long pulse helium discharges reaching 48 min on the Large Helical Device (LHD). Experimental observations show that (i) the wall retention has dynamic characteristics and the differences of the plasma facing material, which are composed of the first wall with...
Dr
Cormac Corr
(Australian National University)
21/10/2016, 14:00
EXD - Magnetic Confinement Experiments: Plasma–material interactions; divertors; limiters; scrape-off layer (SOL)
Poster
Tungsten has been chosen as the material for the ITER divertor and is a contender for the wall of DEMO, which will experience temperatures in excess of 1000 K. The interaction between high-flux helium plasmas with tungsten can lead to plasma-induced surface modifications. In particular helium retention in tungsten is problematic, since helium is known to form nano-scale bubbles beneath the...
Dr
Toru Tsujimura
(National Institute for Fusion Science)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
The central electron temperature of high-ion-temperature plasmas was successfully increased in the large helical device (LHD) up to 7.6 keV for the central ion temperature of 6 keV and a central electron density of 1.4 x 10^(19) m^(-3) by adding a new 154-GHz gyrotron and also by optimization of the ECRH (electron cyclotron resonance heating) injection. The optimization was carried out using...
Dr
Kenji Tanaka
(National Institute for Fusion Science)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
The improvement of the ion energy transport was observed in the He rich plasma of LHD. The ion thermal diffusivity around the edge pedestal region is lower than that of the gyro-Bohm prediction taking into account the effective ion mass and charge. The transport of different ion species is an important issue to predict the performance of ITER and the future reactor operation. In this paper, we...
Dr
Sarah Newton
(Chalmers University of Technology)
21/10/2016, 14:00
THC - Magnetic Confinement Theory and Modelling: Confinement
Poster
Neoclassical accumulation of impurities in the core of hot stellarator plasmas is a known problem.
The complexity of neoclassical transport in stellarators means that few analytic studies are available to support numerical modelling efforts, and a robust understanding of the parameter dependence of the impurity flux is still lacking.
Therefore we present an extension of the existing...
Mr
Yuki Hayashi
(JpUNagoya)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
Handling enormous plasma heat load to divertor is essential to the achievement of high fusion gain. The electron-ion recombination (EIR) process is required to reduce particle flux, leading to reduction of heat load due to the surface recombination. Further, in the ITER research plan, initial studies of H-modes are planned in helium plasmas because the predicted H-mode threshold power in...
Dr
Shinsuke OHSHIMA
(Institute of Advanced Energy, Kyoto University)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
The hydrogen/deuterium (H/D) isotope effects for long range correlation (LRC) and the nonlinear relationship with turbulence were observed for the first time in a helical device, Heliotron J. The fluctuation amplitude and the correlation in toroidal direction in the low frequency range < 4 kHz are enhanced as the D2 gas becomes dominant during the shot-to-shot experiment. Turbulence scale size...
Dr
Giuseppe Mazzitelli
(ENEA)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
The experiments on FTU with a cooled liquid lithium limiter (CLL) (2014&2015) and subsequently with a cooled liquid tin limiter (TLL) (2016) aim at testing liquid metals (LM) under reactor relevant thermal loads of up to 10 MW/m2 in stationary conditions. In preparation of this program, improvements of the FTU facility started in 2014 with: 1) the extension of the pulse duration from 1.5 s up...
Dr
Igor Lyublinski
(RfJSCRedStar)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
Application of powerful (up to 3 MW) ECR plasma heating in Т-10 tokamak with graphite limiters is pulled down with a problem of the plasma pollution at power input more than 2 MW. The use of carbon based limiters leads to formation of carbon films on a surface of a tokamak chamber wall essentially increasing of impurity flux and hydrogen recycling.
For the solution of these problems the new...
Dr
Tokihiko Tokuzawa
(National Institute for Fusion Science)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
We report the discovery of the magnetic island formed in the locked-like mode in helical plasma. New analysis and observation techniques applied to the ECE signal and poloidal flow in LHD experiments show the following results. (i) The magnetic island structure is present. This indicates that the resistive interchange mode can induce the rotating magnetic island in the locking phase. (ii) The...
Prof.
Nikolay Kargin
(NRNU MEPHI)
21/10/2016, 14:00
FIP - Fusion Engineering, Integration and Power Plant Design
Poster
The testing experiments of the Hall sensors based on the gold nanofilms have been carried out in Joint Institute for Nuclear Research in Dubna at the JBR-2 research nuclear reactor in May 2015
The special test instrumentation has been developed to provide the investigation up to the high neutron fluences. The instrumentation permits to provide on-line measurements of the sensor parameters...
Prof.
Shuichi TAKAMURA
(Aichi Institute of Technology)
21/10/2016, 14:00
EXD - Magnetic Confinement Experiments: Plasma–material interactions; divertors; limiters; scrape-off layer (SOL)
Poster
In fusion reactor, the fusion output will be severely restricted by melting of divertor target plate made of W material. Therefore, the artificial impurities such as neon, argon, nitrogen would be injected into edge region to have a strong radiation to the whole plasma-facing surface to mitigate an overheating of a narrow divertor target surface area. Therefore, the divertor plasmas contain...
Dr
Basil Duval
(Ecole Polytechnique Fédérale de Lausanne – Swiss Plasma Center (SPC), Association Euratom-Confédération Suisse(EPFL) CH-1015 Lausanne, Switzerland)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
TCV’s principal goal is to explore and develop the physics basis for ITER exploitation and to aid in the development of DEMO. In the initial design, a combination of X2 and X3 ECH power was planned and installed to provide precision auxiliary heating. With a nominal <1.5T toroidal field strength, X2 heating remains limited to electron densities <~4e10^19/m3 and X3 to electron densities below...
Dr
Alessandro Bruschi
(Istituto di Fisica del Plasma, CNR, Milano, Italy)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
The Collective Thomson Scattering (CTS) diagnostic on FTU tokamak was renewed [1] for investigations on the excitation of Parametric Decay Instabilities (PDI) by Electron Cyclotron (EC) beams in presence of magnetic islands and their effects on the EC absorption.
Experiments were performed with a gyrotron probe (140 GHz, 400 kW) launched in symmetric and asymmetric configurations with respect...
Dr
Satoshi Ohdachi
(National Institute for Fusion Science)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
The central beta of the super-dense-core (SDC) plasma in the Large Helical Device (LHD) is limited by a large scale MHD event called "core density collapse" (CDC). It is found that a new type of ballooning mode, quite localized in space and destabilized from the 3D nature of Heliotron devices, is the cause of the CDC. It is the first observation that the ballooning mode is excited where the...
Dr
Daiji Kato
(National Institute for Fusion Science)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
Visible emission lines of tungsten ions are useful for analysis of tungsten ion distributions at ITER because the radiation shielding of detectors is not basically necessary by using optical fibers. Here we report the result on observation of visible magnetic-dipole (M1) lines of highly-charged tungsten ions in the Large Helical Device (LHD) with tungsten pellet injection and its first...
Dr
Yoshiro NARUSHIMA
(National Institute for Fusion Science)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
New observations in LHD show that the magnetic islands externally imposed by m/n = 1/1 resonant magnetic perturbation (RMP) can be maintained in an intermediate state with a finite phase shift away from the value present in vacuum. The magnetic island is maintained with a deviated phase of around 0.3pi rad from the imposed RMP. The experimental observation implies that the plasma response can...
Dr
Nicola Vianello
(Consorzio RFX, Padova, Italy)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
Addressing the role of Scrape Off Layer filamentary transport is presently a subject of intense studies in fusion science. Indeed, the broadening of the Scrape Off Layer profiles in high density discharges has been observed in a number of devices. The broadening has been attributed to an increase of the convective contribution to the perpendicular transport [LaBombard, B et al. Phys. Plasmas...
Dr
Gerardo Giruzzi
(IRFM, CEA)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
JT-60SA is a large fully superconducting new tokamak device being built under the Broader Approach Satellite Tokamak Programme jointly by Europe and Japan, and under the Japanese national program. The JT-60SA tokamak is due to start operation in 2019 and will be at the forefront of the international fusion programme for many years, both before and during the D-T phase of ITER operation. It...
Dr
Sebastijan Brezinsek
(Forschungszentrum Jülich GmbH)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
Particle and power exhaust compatible with first wall components and the edge plasma is a key area of research and mandatory for a successful operation of ITER and beyond. Within EUROfusion, the research includes tokamak (JET and Medium-Sized Tokamaks) research studies and dedicated laboratory experiments in linear plasma devices, electron and ion beam loading facilities. The connection of...
Dr
Peter Bagryansky
(Budker Institute of Nuclear Physics)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
Active and successful studies of plasma confinement in magnetic mirror traps stopped practically in the late 80's of the last century, despite a number of potential benefits of such systems as the basis for development a nuclear fusion reactor. The reason is that the mirror concept is thought to have three unattractive characteristics. The magnets are complex, the plasma is plagued with...
Dr
Yasuo Yoshimura
(National Institute for Fusion Science)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
Plasmas with the improved electron confinement state, electron internal transport barrier (e-ITB), have been investigated with short pulse discharges (< 1 s). Recent upgrade of ECH system enabled the ECH power up to 0.6 MW at the pulse duration longer than a few minutes. Effective on-axis heating with the increased ECH power realized exploration of the possibility of long pulse sustainment of...
Dr
Federico Felici
(Eindhoven University of Technology)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
To maintain a high-performance, long-duration tokamak plasma scenario, it is necessary to maintain desired profiles while respecting operational limits. This requires real-time estimation of the state of the profiles, monitoring of their evolution with respect to predictions and known limits, and their active control within a desired envelope. Model-based techniques are particularly suitable...
Robert Goldston
(Princeton Plasma Physics Laboratory)
21/10/2016, 14:00
FIP - Fusion Engineering, Integration and Power Plant Design
Poster
We report here advances from earlier work [1] on a lithium vapor box divertor, in which a lithium vapor cloud is held in place by local evaporation and strong differential pumping, forming a target to dissipate the heat flux from the divertor. The lowest, hottest box contains lithium vapor with nl calculated to extinguish the expected heat flux. Its bottom is wetted with a layer of lithium to...
Prof.
Yousuke Nakashima
(Plasma Research Center, JpUTsukuba)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
This paper describes the characteristics of detached plasma produced by using hydrogen and noble gases together with the progress of high-heat and particle flux generation experiments in the GAMMA 10/PDX end-cell. In Plasma Research Center, University of Tsukuba, divertor simulation experiments have been started at the end-cell of GAMMA 10/PDX (E-divertor) [1]. In the GAMMA 10/PDX end-cell,...
Dr
Takuma Wakatsuki
(Japan Atomic Energy Agency)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
Reduction of magnetic flux consumption of a central solenoid (CS) during a plasma current ramp-up phase is investigated using an integrated modeling code suite (TOPICS). It is shown that 27% of the CS flux can be saved in DEMO reactor by 50 MW of EC heating at rho ~ 0.5. The plasma beta is kept low in this scenario. If a safety factor profile should not be a strongly reversed shear profile in...
Dr
Takashi Minami
(Institute of Advanced Energy, Kyoto University)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
A role of rational surface on electron internal transport barrier (eITB) formation of the helical plasma has been investigated in Heliotron J. The experiments have been performed on the standard magnetic configuration of B_{ax} = 1.25 The plasma with eITB is produced by a centrally focused 70 GHz ECR heating ( P_{inj}~270 kW, absorption ratio is above ~90% , N//=0.0) When bootstrap plasma...
Timothy P. Goodman
(EPFL / SPC)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
High power electron cyclotron (EC) waves are used worldwide to drive current locally in the magnetically confined plasmas in toroidal devices. Narrow beams are launched obliquely from antennas well outside the plasma, entering it through the scrape-off layer (SOL) and plasma edge to stabilize neoclassical tearing modes (NTMs).
In nearly all tokamaks, stellarators and reversed-field pinches,...
Dr
Ryuya Ikezoe
(Plasma Research Center, University of Tsukuba)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
High-beta plasma confinement in a mirror field is subject to the influence of the temperature-anisotropy driven mode referred as Alfvén-ion-cyclotron (AIC) wave. The spatial structure of the AIC waves and the enhanced loss of high-energy ions owing to the AIC waves are simultaneously investigated in GAMMA 10 from a standpoint of wave-particle interaction. A clear correlation between the...
Dr
xiaodi du
(National Institute for Fusion Science)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
A bursting resistive interchange mode destabilized by the resonant interaction with the helically trapped energetic ions (EIs), named as the helically trapped energetic-ion-driven resistive interchange modes, or ‘EIC’, has been identified in Large Helical Device (LHD). It can induce the significant loss of the EIs in plasma peripheral region. Therefore, the control of the EICs is important. It...
Dr
Johan Anderson
(Chalmers University of Technology)
21/10/2016, 14:00
THC - Magnetic Confinement Theory and Modelling: Confinement
Poster
During recent years an overwhelming body of evidence shows that the overall transport of heat and particles is to a large part caused by intermittency (or bursty events) related to coherent structures. One of the main challenges in magnetic fusion research has been to predict the turbulent heat and particle transport originating from various micro-instabilities. The ion-temperature-gradient...
Dr
Yukio Nakamura
(National Institute for Fusion Science)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
Impurity behavior in normal long pulse hydrogen discharges with a flat density profile is investigated in a wide operational range and steady state operational regimes providing stationary radiation loss conditions at an acceptable level are explored in LHD. As reported before, impurity transport studies in long pulse discharges provide two different physical pictures based on neoclassical...
Dr
Shinji Kobayashi
(IAE, Kyoto Univ.)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
In this study, we report on the H-mode transition triggered by high-intensity gas puffing (HIGP) in NBI plasmas of Heliotron J. Heliotron J is a medium sized (R/a = 1.2/0.17m) helical-axis heliotron device with an L/M=1/4 helical coil, where L is the pole number of the helical coil and M is the pitch number. An H-mode transition has been observed in the high density NBI plasmas. In the H-mode...
Dr
Alexander Melnikov
(NRC 'Kurchatov Institute')
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
The new finding in study of geodesic acoustic modes (GAMs) on the T-10 tokamak since the last IAEA FEC 2014 are described. The broadband oscillations of plasma electric potential and density in Ohmic and ECRH regimes are measured by Heavy Ion Beam Probe (HIBP) in the core plasma. At the periphery, at r/a > 0.8, the dominated GAM peak with frequency ~ 14 kHz and noticeable peak of...
Mr
Maxim Nurgaliev
(National Research Centre "Kurchatov Institute")
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
The results of impurity (C, O, Ar, K, Fe, and W) transport investigation in OH and ECRH discharges on the T-10 tokamak are presented in this paper. The main attention is paid to a study of the impurity removal from the plasma center during ECRH.
It is shown that in the ohmic discharges neoclassical accumulation of impurities near the plasma axis occurs. This process enhances the effect of...
Dr
Benedikt Geiger
(Max-Planck Institut für Plasmaphysik)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
The behavior of fast particles in high temperature plasmas must be understood in view of future fusion devices. Fast particles result as a product of the fusion process and can be generated by neutral beam injection (NBI) or ion cyclotron heating. They heat the background plasma via collisions on electrons and ions and can, in case of an anisotropic velocity space distribution, drive...
Prof.
Kazunobu Nagasaki
(Institute of Advanced Energy, Kyoto University)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
Experiments of suppressing Alfvén Eigenmodes (AE) have been made by using a second harmonic X-mode electron cyclotron current drive (ECCD) in the helical-axis heliotron device, Heliotron J. The weak magnetic shear under vacuum condition is modified into a positive magnetic shear when counter-ECCD is applied. The experiments show that global Alfvén eigenmodes (GAE) of around 130 kHz and 350 kHz...
Dr
Nikolai Gorelenkov
(PPPL, Princeton University)
21/10/2016, 14:00
EXW - Magnetic Confinement Experiments: Wave–plasma interactions; current drive; heating; energetic particles
Poster
The International Tokamak Experimental Reactor (ITER) will have a large population of non-thermal, energetic ions consisting of fusion generated alphas and beam ions injected for current profile control. Potential redistribution and/or loss of those non-thermal ions is thus of concern as it will modify heating profiles, current profiles, and losses could lead to unacceptable local heating of...
Dr
Sven Wiesen
(Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung – Plasmaphysik, Partner of the Trilateral Euregio Cluster (TEC), 52425 Jülich, Germany)
21/10/2016, 14:00
EXD - Magnetic Confinement Experiments: Plasma–material interactions; divertors; limiters; scrape-off layer (SOL)
Poster
Identification of the mechanisms for the H-mode density limit in machines with fully metallic walls, and their scaling to future devices is essential to find for these machines the optimal operational boundaries with the highest attainable density and confinement. Systematic investigations of H-mode density limit plasmas in experiments with deuterium and hydrogen external gas fuelling have...
Dr
BENOIT LABIT
(Swiss Plasma Center (SPC) EPFL SWITZERLAND)
21/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
Dedicated experiments have been performed in TCV to investigate the heat flux onto the first wall of inboard limited L-mode plasmas. An enhancement of the heat deposition, measured with an infrared (IR) camera, is observed in the vicinity of the contact point. Indeed, for all the discharges, the parallel heat flux profile exhibits a double decay length in the scrape-off layer (SOL), with a...
