Dr
Siriyaporn Sangaroon
(Department of Physics, Mahasarakham University, Mahasarakham, Thailand)
10/20/16, 2:00 PM
THD - Magnetic Confinement Theory and Modelling: Plasma–material interactions; divertors, limiters, SOL
Poster
The tritium is considered as one of main fuels for D-T nuclear fusion reactors, where it is planned to be produced from a blanket of reactors by using the interactions between 14.1 MeV neutrons from nuclear fusion reactions and lithium from the blankets. In this work, the simulations of the tritium production from mock-up breeding blanket due to interactions of neutrons and lithium in the...
Dr
Clayton Myers
(Princeton Plasma Physics Laboratory)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
Halo currents are known to exhibit non-axisymmetric and rotating features in several devices including JET, Alcator C-Mod, DIII-D, ASDEX Upgrade, and NSTX. Such non-axisymmetries are of great interest to ITER because they can increase mechanical stresses during a disruption, especially if the rotation resonates with the natural frequencies of the vessel. This paper presents an ITPA-initiated...
Dr
Christian Hopf
(Max-Planck-Institut für Plasmaphysik)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
Neutral beam current drive (NBCD) is an efficient option for non-inductive tokamak operation. With its eight 2.5 MW neutral beams of different geometry ASDEX Upgrade offers a versatile NBI system, well suited for current drive studies.
Past studies comparing on- and off-axis NBCD at 5 MW gave contradictory results. To understand the current profiles constrained by MSE anomalous fast-ion...
Dr
Felix Reimold
(Forschungszentrum Jülich)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
Future fusion devices like ITER and DEMO will have to be operated with a detached divertor to meet material limits. Stable H-mode operation at high heating power $P_{Heat}/R = [5-12]MW m^{-1}$ with both targets completely detached, confinement of $H_{98}= 0.8 - 0.95$ and Greenwald fraction of $f_{GW}=0.7-0.9$ has been demonstrated with nitrogen seeding in the all-tungsten ASDEX Upgrade...
Dr
Adrianus Sips
(JET Exploitation Unit)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
In the last two years the Integrated Operation Scenarios Topical Group (IOS-TG) of the ITPA IOS-TG has combined results of joint experiments with other data available at q95~3 in a database of global parameters with ~3300 entries of stationary discharges from AUG, C-Mod, DIII-D, JET and JT-60U for both carbon wall and metal wall experiments. The analyses focus on discharges that are stationary...
Dr
Brian LaBombard
(MIT)
10/20/16, 2:00 PM
THD - Magnetic Confinement Theory and Modelling: Plasma–material interactions; divertors, limiters, SOL
Poster
The challenges that will be facing the divertor in a tokamak-based fusion reactor prompt the search for innovative divertor configurations that use non-standard magnetic geometry and additional X-points. Standard tokamak edge plasma transport codes such as UEDGE and SOLPS can be invaluable tools for exploration and evaluation of alternate divertor configurations for potential performance...
Dr
Ivo Furno
(EPFL- CRPP)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
TORPEX is a flexible basic plasma device in which plasmas are created and sustained by microwaves at 2.45GHz using different gases. Different magnetic configurations of relevance for fusion are produced in TORPEX, including simple magnetized toroidal (SMT) configurations with a dominant toroidal field and a small vertical field component, or closed field-line configurations using a...
Dr
William Tang
(Princeton Plasma Physics Laboratory)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
Building the scientific foundations needed to develop fusion power in a timely way can be facilitated not only by familiar “hypothesis-driven”/ first principles approaches but also by engaging modern big-data-driven statistical methods featuring machine learning (ML). An especially time-urgent and very challenging problem facing the development of a fusion energy reactor today is the need to...
Prof.
Wonho Choe
(Korea Advanced Institute of Science and Technology)
10/20/16, 2:00 PM
THD - Magnetic Confinement Theory and Modelling: Plasma–material interactions; divertors, limiters, SOL
Poster
Application of toroidally non-axisymmetric (3D) magnetic fields has great impacts on the heat transport onto divertor target. The 3D magnetic fields form stochastic field layers by opening magnetic islands, leading to modifications of magnetic field structure and heat flux distribution on the divertor. The heat flux splitting pattern strongly depends on the applied field configuration, which...
Dr
Vladislav V Plyusnin
(Instituto de Plasmas e Fusão Nuclear, IST, Universidade de Lisboa)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
Report presents a survey of experiments on runaway electrons (RE) carried out recently in frames of EUROFusion Consortium in different tokamaks (Compass, ASDEX-Upgrade (AUG), TCV and JET). The increase of geometrical scale and physical parameters of plasma experiment on disruption generated RE has been studied. New data on disruption generated RE in Compass with carbon limiter and AUG with...
Dr
Naoko Ashikawa
(National Institute for Fusion Science)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
Generation and accumulation of metal dust particles are important issues in material migration of the Plasma Facing Components (PFCs) such as tungsten (W) and Beryllium (Be) from viewpoints of the plasma operation, maintenance and safety in accidents for ITER and Demo. On the other hand, analysis results of the material components and the internal structure of the dust particle are few because...
Dr
Michael Komm
(Institute of Plasma Physics of the Czech Academy of Sciences)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
The COMPASS tokamak is equipped with a set of high resolution diagnostics, which are capable of resolving the pedestal and hence contribute to the multi-machine scaling of the pedestal parameters. The first results obtained for a series of shots at q95 ~ 2.5 in 2015 confirmed that typical pedestal dimensionless parameters obtained at COMPASS are close to those achieved in a multi-machine...
Dr
Alexey Vertkov
(JSC “Red Star”)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
Capillary-porous systems (CPS) with liquid Li, Ga, Sn and Sn-Li alloy is considered as alternative decision under development of plasma facing elements (PFE) for DEMO-type fusion reactor and fusion neutron source. The main advantages of liquid low melting metals in matrix of CPS with respect to solid materials are the possibility to provide surface self-restoring and high resistance to...
Dr
Tuomas Tala
(VTT)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
Particle transport and fuelling are one of the major open questions in understanding the ITER physics. Core particle transport has been studied in JET by performing a dimensionless collisionality scan both in H-mode and L-mode plasmas. Gas puff modulation technique was exploited to obtain particle transport coefficients and understand details of the neutral particle source.
The dimensionless...
Dr
Justyna Grzonka
(Warsaw University of Technology)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
Comprehensive and systematic surveys of dust particles were performed at JET with the ITER-Like Wall (JET-ILW) after two experimental campaigns, ~19 h of plasma each. Thought the total amounts removed were small (around 1g) the study of dust categories is crucial for ITER because these are unique data from a full metal-wall (beryllium and tungsten) machine. The identification of various...
Mr
Tianyang XIa
(Institute of Plasma Physics, Chinese Academy of Sciences)
10/20/16, 2:00 PM
THD - Magnetic Confinement Theory and Modelling: Plasma–material interactions; divertors, limiters, SOL
Poster
In this paper we report the simulations of the evolution of heat flux deposition and turbulence in edge plasma region for the ELMy H-mode discharges of EAST, C-Mod and DIII-D. The divertor sheath boundary conditions have been implemented into the BOUT++ six-field two-fluid model based on the Braginskii equations with non-ideal physics effects. This module has shown the comparable transient...
Dr
Aleksey Arakcheev
(Budker Institute of Nuclear Physics)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
Simulations of transient heat load corresponding to unmitigated ELMs type I in ITER divertor are performed on novel material test facility developed at the Budker Institute of Nuclear Physics. Employing of intense long pulse (0.1-0.3 ms) electron beam as a heating source results in relative low light emission by the ablation plume hence facilitates imaging of the tungsten target during the...
Dr
Paola Mantica
(Istituto Di Fisica Del Plasma, Consiglio Nazionale delle Ricerche (CNR), 20125 Milan, Italy)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
The TEM driven electron heat transport has been investigated experimentally in JET C-wall L-mode plasmas with dominant ICRH electron heating, by flux scans at constant total electron power and power modulation using ICRH in (3He)-D mode conversion scheme. The dependence of the TEM threshold on s and q has been studied by implementing ad hoc time waveforms of the plasma current in order to...
Mrs
Juan Huang
(CnIPPCAS)
10/20/16, 2:00 PM
THD - Magnetic Confinement Theory and Modelling: Plasma–material interactions; divertors, limiters, SOL
Poster
On the EAST tokamak, resonant magnetic perturbations (RMPs) have been successfully applied to control edge localized mode (ELM) [1]. To quantify the impact of the resulting 3D magnetic field structure on the edge plasma transport, the EMC3-EIRENE code [2] is employed, which is a coupled code package of EMC3 for fluid ions and electrons and EIRENE for kinetic neutrals. The code had been applied...
Dr
Dmitiriy Borodin
(Forschungszentrum Jülich GmbH)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
Erosion will be one of the main factors determining the lifetime of the plasma-facing components (PFCs) in ITER, particularly the low Z beryllium (Be) first wall (FW). This paper presents the tests of Be erosion data during experiments with the ITER-Like Wall (ILW) in JET and the corresponding re-visiting of the predictive modelling for ITER. The key tool is the Monte-Carlo 3D impurity...
Dr
Florian Koechl
(Vienna University of Technology, Institute of Atomic and Subatomic Physics)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
Operation of tokamaks with W PFCs presents specific challenges for impurity control. Lack of impurity control can lead to a radiative collapse due to W accumulation and increased disruptivity. W accumulation in stationary H-mode can be avoided by controlled ELM triggering and central RF heating. Such schemes are also expected to be effective in ITER. However, the control of W transport can be...
Prof.
Jaime Mora-Meléndez
(Instituto Tecnológico de Costa Rica)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
Since 2009, the Instituto Tecnológico de Costa Rica started a research project on stellarators which aims at designing, constructing and implementing the first device of this technology in Latin America. SCR-1 is a small-size, modular stellarator (Major radius=0.238 m, plasma radius=0.059 m, aspect ratio>4.4, expected plasma volume ≈ 0.016 m^3, 10 mm thickness 6061-T6 aluminum vacuum vessel)....
Prof.
Marek Rubel
(Royal Institute of Technology (KTH), Stockholm, Sweden)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
M. Rubel
EUROfusion Consortium, JET, Culham Science Centre (CSC), Abingdon, OX14 3DB, UK
Royal Institute of Technology (KTH), 100 44 Stockholm, Sweden
All plasma-facing components in ITER will be castellated. A large scale test of castellated PFC is carried out at the JET tokamak which has been operated since year 2011 with the metal ITER-Like Wall (JET-ILW). This contribution is...
Gabriella Pautasso
(IPP, Garching, Germany)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
Plasma disruptions, occurring above a given plasma current and thermal energy, will have to be mitigated in ITER, to avoid or suppress runaway electrons, reduce thermal and mechanical stresses on the machine components, and mitigate their damage. The necessary conditions for the fulfillment of – what is called here - the Disruption Mitigation Function (DMF) are, firstly, the capability of...
Prof.
João P. S. Bizarro
(Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Portugal)
10/20/16, 2:00 PM
THD - Magnetic Confinement Theory and Modelling: Plasma–material interactions; divertors, limiters, SOL
Poster
Anomalous transport, turbulence and generation of large-scale structures in the scrape-off layer (SOL) of tokamaks are some of the main issues that control machine performance (via impurity contamination) and the life expectancy of plasma-facing materials, and here one tries to achieve some understanding of these questions through the theoretical analysis of a reduced two-dimensional two fluid...
Dr
Sven Wiesen
(Forschungszentrum Jülich)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
JET ITER-like wall (ILW) experiments show that the edge density evolution is linked with the level of recycling as with increasing density a delay is observed before pedestal recovery after an ELM. Poor confinement in high-density baseline scenarios can be partially mitigated by choosing divertor plasma configurations with the strike-lines close to the divertor corners with enhanced pumping....
Dr
Hiroki Hasegawa
(National Institute for Fusion Science)
10/20/16, 2:00 PM
THD - Magnetic Confinement Theory and Modelling: Plasma–material interactions; divertors, limiters, SOL
Poster
It is firstly demonstrated that transport of impurity particles are caused by blob and hole propagations by means of the three dimensional (3D) electrostatic Particle-in-Cell (PIC) simulations. We have shown that (1) the impurity profile in the blob / hole structure becomes biased shape like a dipole and (2) the biased density profile of impurity propagates with the blob / hole. The "blob" and...
Dr
Alexei POLEVOI
(ITER Organization)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
ELM mitigation for divertor protection is one of the main factors affecting plasma fuelling and detachment control at full current operation. Here we derive the scaling for the operational space, where the ELM mitigation for divertor protection is not required and parameters of ELM-pacing pellet injection are determined by the tungsten control. The scaling eliminates the uncertainty connected...
Dr
Joydeep Ghosh
(Institute for Plasma Research)
10/20/16, 2:00 PM
THD - Magnetic Confinement Theory and Modelling: Plasma–material interactions; divertors, limiters, SOL
Poster
Neutral particle behavior in Aditya tokamak, which has a circular poloidal ring limiter at one particular toroidal location, has been investigated using DEGAS2 code [1]. The code calculations are based on Monte Carlo algorithms and mainly used in the various tokamaks with divertor configuration. This code has been successfully implemented in Aditya tokamak with limiter configuration and the...
Prof.
Jean-Marie Noterdaeme
(Max-Planck-Institute for Plasma Physics)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
The coupling of power in the Ion Cyclotron Range of Frequency to the plasma has encountered challenges, which can be classified into two broad ranges of categories: the sensitivity to the plasma edge density profile with the difficulty to couple power to the plasma and the enhanced plasma-antenna interaction with, among others, the resulting impurity production.
We report on the recent...
Dr
Marc Goniche
(CEA, IRFM)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
Development of high performance plasma scenarios in high Z metal plasma-facing environment is hampered by an unfavourable distribution of these particles across the plasma core, known as ‘core accumulation’. Tungsten core profiles have been analysed in different JET scenarios (Ip=2.5-4.0MA, Ptot=18-30MW) with ICRH (0-6MW, H minority heating) from the soft X-ray diagnostic.
At a plasma...
Dr
Eleonora Viezzer
(Max-Planck-Institut fuer Plasmaphysik)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
The gradients in the ion and electron temperature profiles, Ti and Te, are a key component for
driving turbulent transport in plasmas. Since the 1980s, ‘profile resilience’ has been observed on
many tokamaks, which describes the fact that Ti and Te are limited by a critical normalized temperature gradient. Beyond this critical R/LT the heat diffusivities increase drastically. Hence, with...
Dr
Kristel Crombe
(Ghent University, Belgium)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
IShTAR (Ion Sheath Test ARrangement) is dedicated to the investigation of the interactions between
an ICRF antenna and a plasma in the conditions (plasma temperature and density, magnetic
configuration) representative of the plasma edge of a magnetic confinement fusion machine. The
test bed is composed of a helicon plasma source and a main vessel, in which a dedicated single strap
ICRF...
Mr
Shohei Yamoto
(Faculty of Science and Technology, Keio University, Japan)
10/20/16, 2:00 PM
THD - Magnetic Confinement Theory and Modelling: Plasma–material interactions; divertors, limiters, SOL
Poster
With the move in current and future fusion devices to all-metal walls, and particularly with tungsten (W) plasma-facing components, understanding heavy ion impurity transport processes in the Scrape-Off Layer (SOL)/divertor region is becoming one of the most critical issues for tokamak operation. To improve this understanding, we are continuing to develop the kinetic SOL/divertor impurity...
Mr
Randy Churchill
(Princeton Plasma Physics Laboratory)
10/20/16, 2:00 PM
THD - Magnetic Confinement Theory and Modelling: Plasma–material interactions; divertors, limiters, SOL
Poster
Simulations using the fully kinetic code XGCa were undertaken to explore the impact of kinetic effects on scrape-off layer (SOL) physics in DIII-D H-mode plasmas. XGCa is a
total-f, gyrokinetic code which self-consistently calculates the axisymmetric electrostatic potential and plasma dynamics, and includes modules for Monte Carlo neutral transport. Fluid simulations are normally used to...
738.
Long-term fuel retention and release in JET ITER-Like Wall at ITER-relevant baking temperatures
Dr
Kalle Heinola
(University of Helsinki)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
JET with its ITER-Like Wall (ILW) material configuration is presently the only machine in which ITER-relevant plasma-material interactions, such as material erosion and migration and in-vessel fuel retention and removal, can be studied on the tokamak-scale. Especially the in-vessel tritium (T) retention in ITER has high safety importance. The ITER baseline to recover the trapped T is to...
Dr
Jan Mlynar
(CzIPP)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
Significant role of MHD effects in mitigation and losses of Runaway Electrons (RE) was documented in dedicated experimental studies of RE at the COMPASS tokamak. The MHD activity analyses were based on data from the extensive magnetic diagnostic system of COMPASS, while the RE losses were monitored by the hard X-ray (HXR) scintillation detectors.
RE in COMPASS are normally produced in the...
Dr
Valentin Igochine
(Max-Planck-Institute for Plasma Physics, Garching, Germany)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
The improved H-mode scenario (or high β hybrid operations) is one of the main candidates for high-fusion performance tokamak operation, which could potentially reach the steady-state condition. In this case, the normalized pressure β_N must be maximized and pressure driven instabilities limit the plasma performance. These instabilities could have either resistive ((m=2,n=1) and (3,2)...
Mr
riccardo roccella
(ITER Organization)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
The causes of plasma asymmetries and rotation during disruptions are still an open issue even though their effects are clearly seen on present machines like JET where the vessel has been observed to move horizontally during asymmetric VDEs. Strong horizontal forces are then expected to be related to the plasma asymmetries. In ITER, loads caused by asymmetric VDEs are expected to be among the...
Dr
Andreas Kirschner
(DeIECR)
10/20/16, 2:00 PM
THD - Magnetic Confinement Theory and Modelling: Plasma–material interactions; divertors, limiters, SOL
Poster
Tungsten is a promising first wall material in fusion devices. Though, due to its high atomic number, tungsten concentration levels in the plasma core have to be kept small. However, in addition to low sputtering yields the high atomic number has the beneficial effect of prompt deposition, i.e. depending on the plasma parameters large amounts of sputtered tungsten can be deposited during the...
Dr
Peter De Vries
(ITER Organization)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
The controlled shutdown is an often overlooked, though important, phase of the tokamak discharge. The dynamics during this phase complicate control, making it difficult to avoid operational limits, which in the worst case, may lead to a disruption. This is exacerbated by the fact that at the end of the discharge the device is already operated close to many of its technical limits. For...
Dr
Rodolphe D'Inca
(MaxPlanck Institute for Plasma Physics)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
Ion Cyclotron Emission (ICE) is an instability triggered by the resonant interaction between a population of fast ions and waves supported by the background plasma. The analysis of the signal passively measured with Radio-Frequency probes in time and frequency domains can provide information on the characteristics of the barely trapped and lost fusion alpha-particles in a machine such as ITER....
Dr
Nicolas Mellet
(PIIM, CNRS/Aix-Marseille Univ., France)
10/20/16, 2:00 PM
THD - Magnetic Confinement Theory and Modelling: Plasma–material interactions; divertors, limiters, SOL
Poster
Power exhaust constitutes one of the primary challenges for future fusion devices. Given the fact that scaling parameters have not been clearly identified, the prediction for divertor plasma conditions relies mainly on simulation with transport edge codes like Soledge2D-Eirene that is used in the present work. For charged species, treated with a fluid model, the simulation domain does not...
Daren Stotler
(Princeton Plasma Physics Laboratory)
10/20/16, 2:00 PM
THD - Magnetic Confinement Theory and Modelling: Plasma–material interactions; divertors, limiters, SOL
Poster
Neutral particle recycling effect on the edge ITG (ion temperature gradient) turbulence has been studied in a realistic tokamak geometry with a steep edge pedestal, using a full-f edge gyrokinetic code XGC1. The ITG turbulence is chosen here because it is the most
fundamental and robust form of tokamak plasma instability, with its long radial correlation length influencing other turbulence in...
Mr
Henri Weisen
(JET EFDA)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
The ability to calculate and predict the neutron yield is essential for the planning of fusion experiments, such as the future Deuterium/Tritium experiment in JET. The fusion yield expected in JET from fast ion orbit calculations using NUBEAM/TRANSP has been systematically compared to the measurements from a set of three Uranium fission chambers, which were recalibrated in 2013. In many JET...
Xueqiao Xu
(Lawrence Livermore National Laboratory)
10/20/16, 2:00 PM
THD - Magnetic Confinement Theory and Modelling: Plasma–material interactions; divertors, limiters, SOL
Poster
Simulations with the BOUT++ code have been used to study the energy loss for edge localized modes (ELMs) at different collisionality & electric field Er shear and to investigate the controls of transition to different ELM and quiescent H-mode (QH-mode) regimes. The simulation results indicate that by development of a flexible Er control capabilities, it is conceivable that tokamak operation...
Dr
Roman Zagorski
(Institute of Plasma Physics and Laser Microfusion)
10/20/16, 2:00 PM
THD - Magnetic Confinement Theory and Modelling: Plasma–material interactions; divertors, limiters, SOL
Poster
JT-60SA is a superconducting tokamak supporting fusion research on the way towards realization of energy production in a DEMO reactor. The baseline JT-60SA design foresees full carbon wall, however feasibility studies have been initiated recently to assess the possibility of the transition to full W. In this paper, JT-60SA reference design scenarios at high (#3) and low (#2) density have been...
Mr
Florian Effenberg
(Department of Engineering Physics, University of Wisconsin - Madison)
10/20/16, 2:00 PM
THD - Magnetic Confinement Theory and Modelling: Plasma–material interactions; divertors, limiters, SOL
Poster
Heat flux mitigation and power dissipation is a crucial and challenging topic in the 3-D environment of stellarator devices foreseen for steady state operation. We show that the limiter startup configuration of the first quasi-isodynamic optimized stellarator Wendelstein 7-X features a complex helical scrape-off layer topology of helical scrape-off layer flux bundles of three different...
Mr
Yasuji Hamada
(NIFS)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
Observation of KBM and MTM in JIPPT-IIU tokamak plasmas using a heavy ion beam probe
Hamada Y.*, Watari T., Nishizawa A., Narihara K., Ida K., Kawasumi Y., Ido T., Nakanishi H., Toi K. and JIPPT-IIU Group
National Institute for Fusion Science, Oroshi, Toki, Gifu 509-5292, Japan
E-mail: hamada.yasuji @toki-fs.jp
There is a long history of research of magnetic fluctuations of...
Dr
Joseph Snipes
(ITER Organization)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
The Preliminary Design of the ITER Plasma Control System (PCS) has been carried out since 2014 by members of the ITER Organization and a number of plasma control experts from CCFE, CEA-Cadarache, CREATE, Efremov, General Atomics, IPP-Garching, and Kurchatov as well as through a collaboration with Eindhoven University of Technology. This work builds on the PCS Conceptual Design that was...
Dr
Kenzo Ibano
(Osaka University)
10/20/16, 2:00 PM
THD - Magnetic Confinement Theory and Modelling: Plasma–material interactions; divertors, limiters, SOL
Poster
Erosions of the wall materials via melting, sputtering, and vaporization caused by the intense pulsed heat loads during ELMs and disruptions in the fusion devices are the serious concern. At the same time, experimental observations have shown that the intense heat flux causes the formation of vapor layer which dissipates further incoming plasma heat-flux. Understandings on these...
Prof.
Isao Katanuma
(University of Tsukuba)
10/20/16, 2:00 PM
THD - Magnetic Confinement Theory and Modelling: Plasma–material interactions; divertors, limiters, SOL
Poster
It is understood that plasma blobs produced near a separatrix are responsible for the most radial transport of plasma density in SOL. Particle simulation was first performed on a blob from its production to the propagation. The particle simulation uses the (2 and 1/2) dimensional electrostatic implicit code with 256 x 128 meshes. Ions (electrons) are distributed to have a tanh(x) density...
Mr
Frederic Clairet
(CEA)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
Plasma turbulence is a key parameter governing the confinement quality of magnetically confined plasmas. It is responsible of a substantial particle and heat transport that affects the performance of a nuclear fusion device. More detailed knowledge and understanding are constantly needed and requires more and more precise measurements with, in turn, improved diagnostic performance. Swept...
Dr
Jeremy Lore
(ORNL)
10/20/16, 2:00 PM
THD - Magnetic Confinement Theory and Modelling: Plasma–material interactions; divertors, limiters, SOL
Poster
The 3D edge transport code EMC3-EIRENE is used to test magnetic field models with and without plasma response against experimental data on DIII-D and NSTX for a range of collisionalities, including the transition to detachment. None of the models tested can quantitatively reproduce the measured ‘lobe’ structure in the scrape off layer (SOL) temperature and density while maintaining the...
Markus Weiland
(Max-Planck-Institut für Plasmaphysik)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
Fast, supra-thermal ions provide a powerful mechanism to heat fusion plasmas and to drive plasma currents and rotation. It is therefore crucial for the success of future fusion devices (such as ITER and DEMO) to understand the physics of fast ions and ensure their safe confinement. In the presented work, experimental studies of the fast-ion phase space are carried out using a FIDA (Fast-Ion...
Prof.
Piero MARTIN
(Consorzio RFX)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
EUROfusion dedicates a significant effort to disruption and runaway electron (RE) research in its Medium Size Tokamaks (MST) Task Force, which coordinates the European activities in ASDEX-Upgrade (AUG), MAST-U and TCV. The MST disruption and RE programme addresses prediction, avoidance and mitigation.
Experiments on disruption mitigation utilize Massive Gas Injection (MGI) systems in AUG and...
Dr
David Humphreys
(General Atomics)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
Control analysis and design tools developed at DIII-D [1] have been applied to ITER in studies supporting design of the ITER Plasma Control System (PCS) [2] to prepare for the upcoming PCS Preliminary Design Review (PDR). These studies include assessment of an extremum-seeking approach to real-time error field correction, advances in vertical controllability metrics, simulation of plasma...
Dr
Michael Lehnen
(ITER Organization)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
Successful operation of ITER and a timely achievement of its objectives require an accurate disruption management as the significant disruption loads can have severe impact on the availability of the device and the lifetime of the in-vessel components. Target values for the disruption rate and the mitigation success rate will have to be defined for each of the different operational phases....
Prof.
Ahmed Hassanein
(Purdue University)
10/20/16, 2:00 PM
THD - Magnetic Confinement Theory and Modelling: Plasma–material interactions; divertors, limiters, SOL
Poster
Plasma-material interaction (PMI) in future Tokamak fusion devices such as ITER is probably the most critical issue in the development of fusion power and a serious obstacle that is difficult to overcome. Plasma instability events such as disruptions, resulting runaway electrons, edge-localized modes (ELM), and vertical displacement events (VDE) are all very serious events and potentially the...
Dr
Xianzhu Tang
(Los Alamos National Laboratory)
10/20/16, 2:00 PM
THD - Magnetic Confinement Theory and Modelling: Plasma–material interactions; divertors, limiters, SOL
Poster
The divertor and first wall surface not only recycles the plasma particles
as returned neutrals
but also returns a portion of the impacting ion kinetic energy to the
plasma. Unlike carbon tiles, tungsten walls, for the much larger atomic mass,
mostly reflect the impacting light ions and hence recycle a majority
of the plasma ion kinetic energy.
This hinders the plasma energy exhaust and...
Dr
Matthias Willensdorfer
(Max Planck Institute for Plasma Physics)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
At ASDEX Upgrade ELM mitigation using external magnetic perturbations has been achieved at high plasma densities (n_e/n_GW > 0.65, corresponding to nu*>1.2) and, more recently, at low pedestal collisionality (nu*<0.4) accompanied with density pump-out. To investigate the interaction between the plasma response and ELM mitigation, comprehensive experiments using various plasma configurations...
Dr
Mikhail Tsventoukh
(Lebedev Physical Institute RAS)
10/20/16, 2:00 PM
THD - Magnetic Confinement Theory and Modelling: Plasma–material interactions; divertors, limiters, SOL
Poster
Intense plasma-surface interactions are accompanied not only by simple surface erosion and by the plasma pollution, but it also can lead to the intense collective phenomena of the electrical discharge that maintains at the first wall and derives the energy from the main plasma.
As the fusion plasma typically contains a lot of energy and exhibits intense plasma splashes, e.g. in the ELM form,...
Dr
Antti Hakola
(VTT Technical Research Centre of Finland Ltd.)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
The possible start-up phase of ITER with helium plasmas has set the need to understand in detail the interaction between tungsten plasma-facing components (PFCs) and helium. In addition, a smooth start of He plasma operations requires cleaning the vessel wall from residual fuel species and other impurities. To this end, Ion Cyclotron Wall Conditioning (ICWC) is a promising method. We have...
Prof.
Paolo Ricci
(SPC-EPFL)
10/20/16, 2:00 PM
THD - Magnetic Confinement Theory and Modelling: Plasma–material interactions; divertors, limiters, SOL
Poster
The GBS code has been developed in the last few years to simulate plasma turbulence and neutral atom dynamics in SOL conditions. GBS advances the drift-reduced Braginskii equations for low-frequency plasma turbulence, solving at the same time a kinetic equation of neutral atoms by the method of characteristics. In GBS the plasma dynamics is evolved as the interplay between plasma sources (due...
Dr
Carine Giroud
(CCFE)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
The pedestal confinement has significantly decreased in JET with its metallic ITER-like wall with reference to the carbon wall phase of JET (JET-C). In particular, a reduction in pedestal temperature is observed in all scenarios regardless of the level of D-gas injection or value of 𝛽N 1-3¬. At low gas injection, excessive W radiation is not always the cause for this reduction. Unraveling the...
Dr
Patrick Tamain
(CEA Cadarache)
10/20/16, 2:00 PM
THD - Magnetic Confinement Theory and Modelling: Plasma–material interactions; divertors, limiters, SOL
Poster
Mean-field transport codes are the key tools for the understanding of Scrape-Off-Layer and divertor regimes. They rely on models in which simple closures are used to model average fluxes and stresses due to fluctuations. In particular, turbulent transport is commonly described via a gradient-diffusion hypothesis and ad-hoc diffusion coefficients. However, these coefficients differ from one...
Dr
Andreas Kirschner
(DeIECR)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
Plasma-wall interaction in fusion devices results in material erosion of the first wall, its migration and deposition. According to the present knowledge, tritium contained in the co-deposited layers is responsible for the major part of the in-vessel tritium inventory.
A set of quartz crystal microbalance (QMB) was used at JET with full carbon wall to monitor material erosion/deposition rates...
Dr
Jonathan Citrin
(FOM DIFFER - Dutch Institute for Fundamental Energy Research)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
A realtime capable core turbulence tokamak transport model is developed, extending a previous proof-of-principle (J.Citrin, S.Breton et al., Nucl. Fusion 55 092001, 2015). This model emulates a quasilinear gyrokinetic turbulent transport code, via regularized nonlinear regression using neural networks. Calculation of transport fluxes for the entire radial profile is achieved at sub-millisecond...
Dr
Dirk Van Eester
(LPP-ERM/KMS)
10/20/16, 2:00 PM
EXW - Magnetic Confinement Experiments: Wave–plasma interactions; current drive; heating; energetic particles
Poster
Ion cyclotron resonance heating (ICRH) is a powerful and flexible method, which can make a significant contribution to a future DT campaign on JET. It can be used for direct fuel ion heating or for minority ion heating, in the latter case leading to electron heating via Coulomb collisions of the fast minority ions with the electrons. Some ICRH schemes can also directly enhance nuclear reaction...
Dr
Elena de la Luna
(CIEMAT)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
Recent experiments on JET with the ITER-like wall (ILW) show that divertor pumping is a key element to access good confinement at high triangularity in scenarios where high gas injection rates are required to keep W core radiation within acceptable limits (for plasma current above 1.5 MA). Similar to previously reported observations at low-triangularity, the use of a configuration where the...
Dr
Régis Bisson
(Aix-Marseille Université, CNRS, PIIM UMR 7345)
10/20/16, 2:00 PM
THD - Magnetic Confinement Theory and Modelling: Plasma–material interactions; divertors, limiters, SOL
Poster
Fusion fuel trapping (retention) and release from plasma facing components (PFC) is one of the critical issues for ITER and for any future industrial demonstration reactor such as DEMO. Therefore, understanding fundamental mechanisms behind hydrogen isotopes retention in first wall materials is necessary. We developed an approach that couples dedicated experimental studies with modelling at...
Mr
Ammar Hakim
(Princeton Plasma Physics Laboratory)
10/20/16, 2:00 PM
THD - Magnetic Confinement Theory and Modelling: Plasma–material interactions; divertors, limiters, SOL
Poster
We present a new gyrokinetic code, Gkeyll, for use in edge plasma
simulations. The code implements energy conserving discontinuous
Galerkin schemes, applicable to a general class of Hamiltonian
equations. Several applications of our code to various test problems
are presented. We compute the parallel heat-flux on divertor plates
resulting from an ELM crash in JET, for a 1D/1V SOL...
Dr
Michael Campanell
(Lawrence Livermore National Laboratory)
10/20/16, 2:00 PM
THD - Magnetic Confinement Theory and Modelling: Plasma–material interactions; divertors, limiters, SOL
Poster
Electron emission from surfaces is important in many plasma applications. Recently, it was shown that a fundamentally distinct plasma-surface interaction regime denoted the “inverse regime” [1] occurs when the emission coefficient exceeds unity. An inverse regime might arise in divertors because secondary and thermionic emission from divertor plates are intense under certain operating...
Dr
Sergei Sharapov
(CCFE)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
Good confinement of fusion-born alpha-particles is essential for the success of ITER. Modelling with the HAGIS code is performed to compute nonlinear stability of alpha-particle-driven TAEs and redistribution of alpha-particles in the 15 MA baseline ITER scenario. For this modelling, 129 TAEs with n’s from 1 to 35 were computed with the MISHKA code, and their damping effects were assessed with...
717.
Study of the Effect of Magnetic Expansion in Snowflake Divertor on Impurity Screening for CFETR
Prof.
Minyou Ye
(School of Nuclear Science and Technology,cnUSTC)
10/20/16, 2:00 PM
THD - Magnetic Confinement Theory and Modelling: Plasma–material interactions; divertors, limiters, SOL
Poster
Snowflake divertor is considered as a possible choice for CFETR design due to its dramatic ability in reducing the peak heat load onto divertor targets. It was pointed out that, such a reduction of peak heat load is due to both larger plasma-wetted area and larger fraction of power radiated in the edge [M.V. Umansky, et al., Nucl. Fusion 49 (2009) 075005]. Therefore, to achieve the best level...
Dr
Andreas Stegmeir
(Max-Planck-Institute for Plasma Physics)
10/20/16, 2:00 PM
THD - Magnetic Confinement Theory and Modelling: Plasma–material interactions; divertors, limiters, SOL
Poster
The complex geometry in the edge and scrape-off layer poses a challenge to simulations of magnetically confined plasmas, since the usually employed field/flux-aligned coordinates become singular on the separatrix/X-point.
A field line map approach (see also flux-coordinate independent approach) offers a promising solution to these problems. The approach is based on a cylindrical grid, which...
Dr
Marco Valisa
(Consorzo RFX)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
Experimental and modeling activities have started at JET in order to carry out an assessment of the physics mechanisms that control the penetration of high Z impurities from the divertor into the core plasma and to provide firm physics basis for the ELM-control requirements in ITER. The experiments are based on the injection of traces of extrinsic impurities in various ELMy plasmas, thus...
Dr
Yannick Marandet
(PIIM, CNRS/Aix-Marseille Univ., Marseille, France, EU)
10/20/16, 2:00 PM
THD - Magnetic Confinement Theory and Modelling: Plasma–material interactions; divertors, limiters, SOL
Poster
Power exhaust is one of the major challenges that future devices such as ITER and DEMO will face. Because of the lack of identified scaling parameters, predictions for divertor plasma conditions in these devices have to rely on detailed modeling. Most plasma edge simulations carried out so far rely on transport codes, which consist of a fluid code for the plasma coupled to a kinetic Monte...
Dr
Thomas Pütterich
(Max-Planck-Institut für Plasmaphysik)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
The radial electric field E_r at the plasma edge and its relation to plasma turbulence is investigated throughout the LH-transition and an ELM cycle. Various diagnostics are considered including an upgraded charge exchange recombination spectroscopy system. The latter is able to measure impurity temperature, flow and density profiles with a frequency of up to 20kHz and a radial resolution of...
Mr
yann corre
(FrCEAIRFM)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
Tungsten (W) melting by transient power loads, for example those delivered by edge localised modes (ELMs), is a major concern for next step fusion devices. By virtue of its size, the amplitude of unmitigated Type I ELMs on JET can be sufficient to induce transient flash melting at the divertor targets provided a deliberately misaligned element is introduced. A first experiment was performed in...
Dr
Peter Manz
(Max-Planck Institut für Plasmaphysik)
10/20/16, 2:00 PM
EXS - Magnetic Confinement Experiments: Stability
Poster
The I-mode is an improved confinement regime of tokamak plasmas operating in the unfavorable
ion gradB-drift direction combining H-mode-like energy confinement with L-mode-like particle and impurity transport [1]. To qualify the I-mode as an operating scenario for ITER threshold and accessibility studies [2] also on a multi-machine basis [3] are needed. Even if the I-mode might not be...
Dr
Seung-Hoe Ku
(Princeton Plasma Physics Laboratory)
10/20/16, 2:00 PM
THD - Magnetic Confinement Theory and Modelling: Plasma–material interactions; divertors, limiters, SOL
Poster
The importance of the nonlinear "blobby" turbulence (or "intermittent plasma objects") in the scrape-off layer (SOL) of the tokamak plasma has been well known. Blobs are usually measured and discussed for L-mode edge/SOL plasmas and inter-ELM SOL plasmas. However, blobs are also known to exist in steep H-mode pedestals. From ITER’s perspective, understanding the H-mode blobs may be more...
