Prof.
Isao Katanuma
(University of Tsukuba)
14/10/2014, 08:30
Poster
A flute mode is the most dangerous instability in an open system such as the GAMMA10 tandem mirror. So how to stabilize the flute instability is an important problem. This paper studies the stabilizing effects of the ExB shear flow on a flute instability in the Cartesian geometry by the particle simulation and in the GAMMA10 magnetic field by the reduced MHD simulation. The particle simulation...
Dr
Md. Khairul Islam
(Bangladesh Atomic Energy Commission)
14/10/2014, 08:30
Poster
Ion current in ion drift direction as well as the plasma shift in that direction in the localized non-axisymmetric magnetic field region of the anchor cell of the GAMMA 10 tandem mirror were measured. In addition, electron current perpendicular to the ion drift direction was found in this region. To understand these plasma behaviors, relevant kinetic properties of plasma particles are analyzed...
Dr
Yueqiang Liu
(UK)
14/10/2014, 08:30
Poster
Precise determination of resistive instabilities is an outstanding issue in tokamaks, remaining unsatisfactory for a long time despite its importance for advanced plasma control. This paper presents the first successful computation of such resistive instabilities including full mode coupling and multiple singular surfaces, by upgrading DCON [1] with a resonant-Galerkin method [2] using...
Dr
Sanat Kumar Tiwari
(Institute for Plasma Research, Bhat, Gandhinagar, Gujarat)
14/10/2014, 08:30
Poster
In this paper, the quasilinear version of the current evolution equation in the presence of ETG turbulence in the tokamak pedestal region is written down. It has been shown that the current drive has to fight the conventional resistive dissipation mechanism as well as new dissipation mechanisms, such as a turbulence driven hyper-resistivity coefficient associated with the ETG turbulence. It...
Dr
Gianluca Spizzo
(Consorzio RFX, Associazione EURATOM-ENEA sulla Fusione, Padova, Italy)
14/10/2014, 08:30
Poster
Both in the tokamak and the reversed-field pinch (RFP), new finds show that the high density limit, which often disrupts tokamak discharges and slowly terminates RFP ones, is not governed by a unique, theoretically well-determined physical phenomenon, but by a combination of complicated mechanisms involving two-fluid effects, electrostatic plasma response to magnetic islands and plasma-wall...
Dr
Arseniy Kuzmin
(Kyushu University, RIAM, AFRC, Japan, Kasuga)
14/10/2014, 08:30
Poster
A new approach to realize steady state tokamak operation SSTO has been demonstrated in QUEST with all metal wall baked at 100°C. Using particle flux perturbations driven by particle source H2 and plasma-wall interaction PWI the system functions of processes of retention and release into/from the wall are determined both in time and frequency domains. The system function for the particle...
Prof.
William W. Heidbrink
(USA)
14/10/2014, 08:30
Poster
The performance of the burning plasmas is limited by the confinement of superalfvenic fusion products, alpha particles, resonating with the Alfvénic eigenmodes (AEs). Two techniques are developed to evaluate the AE induced fast ion relaxation. Both rely on linear instability theory and are confirmed by experiments. The first is the reduced quasilinear technique or critical gradient model (CGM)...
Dr
Alexey Vertkov
(JSC “Red Star”)
14/10/2014, 08:30
Poster
Development of commercially attractive project of a tokamak based fusion neutron source, intended for the progress in fusion power reactor and fission technology, requires the possibility of plasma facing elements (PFE) to steady-state operation under extremely high power loads.
Cooling of tokamak boundary plasma owing to radiation of none fully stripped lithium ions is considered as a...
Prof.
Sergey Mirnov
(TRINITI)
14/10/2014, 08:30
Poster
During operation on the tokamak T-11M it was achieved almost complete (up to 80%) closing of lithium circulation circuit between the edge of hot (106K) plasma and the chamber wall. Lithium, emitted by the vertical capillary Li limiter during operations of T-11M has been collected by the cryogenic target and removed outside the tokamak vacuum chamber without disturbing of tokamak operation...
Dr
Benedikt Geiger
(Max-Planck-Institut für Plasmaphysik, Garching, Germany)
14/10/2014, 08:30
Poster
The transport of fast, suprathermal ions as generated by neutral beam injection (NBI) is an important topic in fusion research. In unperturbed plasmas the fast-ion transport is expected to be neoclassical, i.e. dominated by collisions, while an anomalous transport is observed in the presence of instabilities. This anomalous fast-ion redistribution must be investigated in detail because it may...
Mr
Nikolay Bakharev
(Ioffe Physical-Technical Institute of the Russian Academy of Sciences)
14/10/2014, 08:30
Poster
Behavior of the fast particle population, arising during 20-30 keV hydrogen and deuterium neutral beam injection in the hydrogen and deuterium plasmas, is investigated. Experiments revealed large fast ion losses. Experimental results are confirmed by different types of modeling: simulation with the NUBEAM module, solution of Boltzmann kinetic equation with Landau collision term and full 3D...
Dr
Manuel Garcia-Munoz
(University of Seville, Spain)
14/10/2014, 08:30
Oral
The fast-ion response to externally applied 3D Magnetic Perturbations (MPs) has been investigated on ASDEX Upgrade (AUG) in H-mode plasmas with a wide range of collisionalities / densities and MP spectra. MPs have little effect on kinetic profiles, including fast-ions, in high collisionality plasmas with mitigated ELMs while a strong plasma (including fast-ions) response is observed in H-mode...
Dr
Michael Leconte
(NFRI)
14/10/2014, 08:30
Poster
We study the feedback loop of a spontaneous magnetic perturbation (neoclassical tearing mode) on a background of drift wave – Zonal Flows, in the framework of a 1D predator-prey model for the evolution of turbulence intensity I(x,t), Zonal Flow energy U(x,t), electron temperature gradient T(x) and island-width. A modified Rutherford equation describes the magnetic island dynamics. The magnetic...
Dr
Gregor Birkenmeier
(Max Planck Institute for Plasma Physics, Garching, Germany)
14/10/2014, 08:30
Poster
At the edge of fusion plasmas, intermittently expelled density filaments, so-called blobs [1], are propagating through the scrape-off layer (SOL) perpendicular to the magnetic field. Due to its higher density and temperature compared with the background SOL plasma, they can lead to a significant degradation of plasma facing components in the main chamber. Since this degradation is critical for...
Dr
Mikhail Malkov
(University of California, San Diego)
14/10/2014, 08:30
Poster
It is believed that L-H transition occurs via coupling of turbulence to low frequency shear flows by Reynolds work. As a consequence, turbulence and turbulent transport collapse, enabling the growth of diamagnetic electric field shear and the transition. This work focuses on the missing link between microscopics and macroscopics, and its critical role in power threshold scaling. The major goal...
Dr
Hiroshi Idei
(Research Institute for Applied Mechanics, Kyushu University)
14/10/2014, 08:30
Poster
28 GHz Electron Cyclotron Current Drive (ECCD) effect was clearly observed in Ohmically heated plasmas with feedback regulation of center solenoid coil current in 2nd harmonic inboard off-axis heating scenario. In non-inductive current drive experiments only by the 28 GHz injection, 54 kA plasma current was sustained for 0.9 s. Higher plasma current of 66 kA was non-inductively obtained by...
Prof.
Michiaki Inomoto
(The University of Tokyo)
14/10/2014, 08:30
Poster
Magnetic reconnection allows highly-conducting plasma to change its magnetic topology in nuclear fusion plasmas, such as sawtooth crash, internal reconnection event, and so on. Recent theoretical and numerical works revealed that the presence of guide field (GF) greatly changes the collisionless reconnection in a qualitative way. One of the essential changes is that electrons are efficiently...
Dr
Viktor Bulanin
(St.Petersburg State Polytechnical University)
14/10/2014, 08:30
Poster
Owing to the active researches of intermediate regime which is known as limit cycle oscillation (LCO) regime, it is important to investigate oscillations of velocity of zonal flows, plasma density and magnetic field simultaneously. The geodesic acoustic mode (GAM) investigations using multi-diagnostic were carried out on the spherical tokamak Globus-M (R = 0.36 m, a = 0.24 m, Ip = 150 kA, BT =...
Dr
Alessandro Biancalani
(Max-Planck-Institut für Plasmaphysik Euratom Association, Garching, Germany)
14/10/2014, 08:30
Poster
In this work, we investigate theoretically the dynamics of global instabilities observed in ASDEX Upgrade (AUG) by means of collisionless numerical simulations. We focus in particular on geodesic acoustic modes (GAM) and shear Alfven instabilities. The numerical tools we use are the codes NEMORB (nonlinear global gyrokinetic PIC), LIGKA (linear global gyrokinetic) and XHMGC (nonlinear global...
Dr
Tuomas Tala
(VTT)
14/10/2014, 08:30
Poster
Previous work performed has amassed a substantial database of intrinsic rotation measurements in various tokamak devices. However, as our understanding of momentum transport has evolved, it has become clear that a reliable prediction of the rotation in future devices requires a more complete momentum transport model and a more fundamental understanding of the mechanisms driving the intrinsic...
Dr
Sergey Lashkul
(Ioffe Physical-Technical Institute, RAS, Russia)
14/10/2014, 08:30
Poster
Current drive by lower hybrid waves (LHCD) is the most effective method to keep the plasma current, but it is feasible only at the plasma density not exceeding some density limit n_DL. In the present work the main attention is paid to investigation of this effect on the FT-2 (R=0.55 m, a=0.08 m, B_T ≤ 3T, I_p=19÷40 kA, f_0 = 920МHz) tokamak. The dependence of LHCD efficiency on isotopic plasma...
Mr
Leonid Klyuchnikov
(Institute of Tokamak Phisycs, National Research Centre "Kurchatov Institute", Moscow, Russia)
14/10/2014, 08:30
Poster
Experiments on impurities removal with central ECR heating on T-10 were carried out with various plasma parameters. CXRS and Zeff measurements show removal of carbon nuclei from plasma during central ECRH.
There is a complex of high-power gyrotrons for ECRH experiments on T-10. Spectroscopic diagnostics of T-10 allows to measure carbon concentration by CXRS diagnostics [1] and to measure...
Dr
Ilya Senichenkov
(Saint Petersburg State Polytechnical University)
14/10/2014, 08:30
Poster
In the present paper the results of integrated modeling of Globus-M tokamak plasma with the help of recently coupled core transport code ASTRA and edge transport code B2SOLPS are presented. In the modeling taken into account are the neoclassical transport, auxiliary heating and current drive by the NBI, 2D drift fluxes, currents and electric field in the edge plasma in a real geometry of...
Mrs
Anastasia Shcherbak
(SRC RF TRINITI)
14/10/2014, 08:30
Poster
Regimes of discharge of improved plasma confinement were found in the experiments with a vertical lithium limiter on T-11M tokamak, which was manifested in spontaneous growth of the electron density up to the limit Greenwald and above. Previously, such modes arising after chamber lithiization were observed in the tokamak FTU. The analysis of data obtained in T-11M has showed that this regime...
Prof.
Kazuaki Hanada
(Advanced Fusion Research Center, Research Institute for Applied Mechanics, Kyushu University)
14/10/2014, 08:30
Poster
Progression from low (LR) to high recycling (HR) was observed in full non-inductive long duration discharges up to 5 minutes on QUEST. Transitional repetitive behavior between LR and HR was induced by periodic gas puffing and the period to recover to LR, tau_rec, was gradually prolonged. The period, tau_rec normalized by gas rate has a linear relation to time-integrated H_alfa. As the...
Dr
Nikolay Ivanov
(Kurchatov Institute)
14/10/2014, 08:30
Poster
The experimental comparison of the m=2 mode and plasma rotation velocities at the q=2 magnetic surface in a range of the mode amplitudes is presented in this paper. The phase velocity of the mode rotation is measured with a set of poloidal magnetic field sensors located at the inner side of the vacuum vessel wall. The plasma rotation velocity at the q=2 magnetic surface in the direction of the...
Dr
Gerardo Giruzzi
(IRFM, CEA)
14/10/2014, 08:30
Poster
An intensive programme has been started in the EU, aiming at a more and more refined selection of the DEMO design. The general strategy adopted consists in developing two DEMO concepts in parallel: a pulsed tokamak, characterised by rather conventional physics and technology assumptions (DEMO1) and a steady-state tokamak, with moderately advanced physics and technology assumptions (DEMO2). The...
Dr
Linda Sugiyama
(Massachusetts Institute of Technology)
14/10/2014, 08:30
Poster
Instabilities with poloidal and toroidal mode numbers m/n=1/1 remain an important concern for fusion in toroidal plasmas. Sawtooth crashes can periodically reduce the central plasma pressure and fusion rate or trigger more dangerous instabilities. Recent experimental results[1-3] have identified new types of 1/1 modes around and inside the q=1 magnetic surface. Nonlinear full MHD numerical...
Mr
Vladimir Rozhdestvensky
(Ioffe-Institute)
14/10/2014, 08:30
Poster
Results of studying the abnormal microwave emission (ME) arising under ohmic heating (OH) of the moderately dense plasma and generation of the low-hybrid current drive (LHCD) in the FT-2 tokamak are presented. The ME appearance is due to the «fan» instability development and the substantial local magnetic ripples existence. It was found that the ME arises continuously during OH in the...
Prof.
Raghvendra Singh
(NFRI-Korea / IPR-India)
14/10/2014, 08:30
Poster
We present a new dynamical model of pedestal ELM phenomena based upon the multi-scale interaction between low-n MHD ballooning mode and short scale ETG turbulence. ELM dynamics are determined by the few basics process results from multi scale interaction. These includes: generation of hyper resistivity ( ) in coupled ballooning mode - ETG turbulence; excitation of hyper resistive BM near ideal...
Mr
Alexey Altukhov
(Ioffe Institute)
14/10/2014, 08:30
Poster
The drift-wave turbulence responsible for anomalous transport of energy and particles in tokamak plasma is widely studied nowadays both experimentally and in theory. An interesting and important prediction of the numerical approach based on full-f gyrokinetic modeling is statistical inhomogeneity of trapped-electron-mode turbulence typical for ohmic discharge. Though the radial variation of...
Dr
Milan Rajkovic
(University of Belgrade, Institute of Nuclear Sciences Vinca)
14/10/2014, 08:30
Poster
Plasma self-organization is the frontier research area in plasma physics and its understanding is extremely important for the construction of innovative fusion configurations. Emergence, an outcome of self-organization, implies the appearance of certain large scale structures, forms or patterns, formed from a large number of simple interactions of smaller parts of the system. Motivated by...
Dr
Eleonora Viezzer
(Max-Planck-Institut für Plasmaphysik)
14/10/2014, 08:30
Poster
The formation of the H-mode transport barrier is strongly connected to the existence of a sheared plasma flow perpendicular to the magnetic field caused by a local radial electric field E_r. The strong gradients in E_r and the associated ExB velocity shear play a fundamental role in edge turbulence suppression, transport barrier formation and the transition to the H-mode. This contribution...
Dr
Matthias Reich
(Max-Planck-Institut für Plasmaphysik, Garching, Germany)
14/10/2014, 08:30
Poster
In high performance plasmas, Neoclassical Tearing Modes (NTMs) are regularly observed at large beta-values. NTMs reduce the achievable normalized beta and degrade the fusion reactor performance which scales as beta_N squared. A widely used method, also foreseen for ITER, for avoiding and controlling NTMs is the deposition of electron cyclotron current drive (ECCD) on the relevant rational...
Dr
Ricardo Farengo
(Comision Nacional de Energia Atomica)
14/10/2014, 08:30
Poster
The internal kink modes associated with sawtooth oscillations can produce a redistribution of the energetic particles population, thus modifying the power deposition profile and increasing particle losses and wall loading. We study the effect of internal kink modes on the confinement of alpha particles and neutral beam ions by following the trajectories of a large number of particles in the...
Mr
kishore mishra
(Kyushu University)
14/10/2014, 08:30
Poster
There is a considerable interest in operating tokamak at high value of beta_p , but maximum attainable beta_p is limited by a equilibrium limit with appearance of a null point at the inboard side. Such configuration is realized transiently earlier by Electron Cyclotron Waves, but in QUEST such equilibrium is stably produced in steady state and its equilibrium properties are investigated. In...
Dr
Hao WANG
(National Institute for Fusion Science)
14/10/2014, 08:30
Poster
A new kind of energetic particle driven geodesic acoustic mode (EGAM), which has weak bulk plasma temperature dependence of frequency, has been found in the Large Helical Device (LHD) experiments. In this work, the new kind of EGAM is investigated with a hybrid simulation code for energetic particles and magnetohydrodynamics (MHD). It is demonstrated that the new EGAM in the simulation results...
Dr
Albrecht Herrmann
(IPP-Garching)
14/10/2014, 08:30
Poster
AUG became a full tungsten experiment in 2007. At this time all plasma facing components have been coated with tungsten. To overcome the disadvantages of the coating - i.e. delamination of thick coatings, fast erosion of thin coatings in particular in the high heat load regime – we started to prepare a new outer divertor with solid tungsten at the outer strike line in 2010. The Div-III design...
Dr
Wolfgang Suttrop
(Max-Planck-Institut für Plasmaphysik)
14/10/2014, 08:30
Poster
ASDEX Upgrade is equipped with two rows of in-vessel saddle coils for magnetic perturbations with toroidal mode numbers up to n=4. A reliable ELM mitigation regime has been found in which large type-I ELMs are suppressed, and replaced by a small form of ELMs with significantly reduced energy loss from the plasma and heat load to the divertor. This regime is accessible at high pedestal plasma...
Dr
Alexander Melnikov
(NRC 'Kurchatov Institute')
14/10/2014, 08:30
Poster
Zonal flows and their high-frequency counterpart, the Geodesic Acoustic Modes (GAMs) are considered as a possible mechanism of the plasma turbulence self-regulation. The paper presents the results of the systematic study of GAM properties in the T-10 tokamak with heavy ion beam probe (HIBP) in the core and with multipin Langmuir probes in the edge. It was shown that GAM has radially...
Dr
Sergey Neudatchin
(IFT, NRC Kurchatov Institute)
14/10/2014, 08:30
Poster
In the present report, we focus at the analysis of four transport processes in T-10. First, we analyze inward electron heat pulse propagation (HPP) created by switch-on of additional off-axis ECRH on a sawteeth-free background sustained by off-axis ECRH. The presence of slow and diffusive inward HPP with “dynamic” hi-e value close to power balance value shows that the so-called “heat pinch” is...
Dr
Igor Roy
(Institute of Tokamak Physics, National Research Centre Kurchatov Institute)
14/10/2014, 08:30
Poster
The auxiliary Heating and Current Drive systems of the T-15upgrade tokamak are presented. The NBI system will consist of three hydrogen NB injectors 6 MW total power at pulse duration up to 30 s. The ECRH and CD system will consist of 7 gyrotrons 6 MW total RF launched power at pulse duration up to 30 s. The LHH and CD system will be able to launch 4 MW RF power with 30 s duration.
Mr
Valeriy Dyachenko
(A.F. Ioffe Physico-Technical Institute)
14/10/2014, 08:30
Poster
The development of quasi-stationary methods of non-inductive current drive in plasmas of spherical tokamaks is extremely important for their using in thermonuclear devices. Specific properties of spherical tokamaks provide the possibilities the current drive by the waves of intermediate frequency range slowed down in poloidal direction. This approach, developed theoretically in the Ioffe...
Dr
Rita Lorenzini
(Consorzio RFX, Corso Stati Uniti 4, 35127, Padova, Italy)
14/10/2014, 08:30
Poster
The isotope effect, namely the dependence of plasma confinement on the mass Mi of majority ion, is a well known property of tokamak configuration. Increasing Mi leads to an improvement of energy, particle and momentum confinement in all regimes of tokamak plasmas. Besides, Mi influences also many MHD roperties, e.g. increasing the period of plasma instabilities. However in stellarators the...
Dr
Ker-Chung Shaing
(University of Wisconsin)
14/10/2014, 08:30
Poster
Error fields or magnetohydrodynamic (MHD) activities break toroidal symmetry in real tokamak fusion reactors, e.g., ITER. It has been shown in a comprehensive theory for neoclassical toroidal plasma viscosity for tokamaks that broken symmetry enhances particle, momentum, and energy transport. The enhanced energy transport increases with increasing energy. Because fusion-born alpha particles...
Dr
Monica Spolaore
(Consorzio RFX, Padova, Italy)
14/10/2014, 08:30
Poster
Filament or blob structures have been observed in all magnetic configurations with very similar features despite the difference in the magnetic geometry: theory and experiments suggest they exhibit a radial convective motion across the SOL, and the interest in blob dynamics is further motivated by their interaction with first wall and divertor.
Despite their different generation mechanism,...
Dr
Didier Mazon
(CEA Cadarache)
14/10/2014, 08:30
Poster
Many tokamaks are nowadays equipped with metallic walls. The positive effect of such modification compared to the previous carbon walls is a strong reduction of the tokamak wall erosion and tritium retention. But the drawback is a production and potential accumulation of heavy impurities in the plasma core which can cause high radiation losses and even trigger radiative collapses often leading...
