Mr
Emmanuel Joffrin
(France)
09/10/2012, 14:00
Poster
In the recent JET experimental campaigns with the new ITER-like-Wall(ILW), major progress has been achieved in the characterisation of the H-mode regime: i) plasma breakdown and L-mode operation have been recovered in a few days of operation, ii) stable type I ELMy H-modes with H98y2 close to 1 and BetaN~1.6 have been achieved in high triangularity ITER–like shape plasmas on the bulk divertor...
Mr
Basil Duval
(Switzerland)
09/10/2012, 14:00
Poster
TCV’s real-time (RT) control system uses a range of diagnostic signals to detect plasma events and react with programmable, controllable actuators such as orientable ECH power and Tokamak control actuators. Three examples of MHD phenomena control are presented with RT recognition of temporal and/or spatial extents of events controlled by synchronous modulation of the power or heating position...
Ms
Amanda Hubbard
(USA)
09/10/2012, 14:00
Poster
The I-mode regime of operation has been extended in recent Alcator C-Mod campaigns in duration and robustness, over a wide range of parameters. This attractive regime features an edge thermal barrier, and H-mode like energy transport, in combination with L-mode like density profiles and particle transport. This prevents accumulation of impurities, and means that ELMs are not needed to expel...
Mr
Joerg Stober
(Germany)
09/10/2012, 14:00
Poster
In contrast to ITER and future fusion reactors, plasmas used today for preparational or fundamental studies are often heated dominantly via the ion channel and with strong concurrent momentum input. This is due to the dominance of NBI heating systems, which are widely used because of their reliability and universal applicability. The potential danger of this approach is an over-estimation of...
Mr
Christopher T. Holcomb
(USA)
09/10/2012, 14:00
Poster
New off-axis neutral beam injection (NBI) capability on DIII-D has expanded the range of achievable and sustainable current and pressure profiles of interest for developing the physics basis of steady-state scenarios in future tokamaks. Fully noninductive (NI) scenarios are envisioned to have broad current and pressure profiles with elevated minimum safety factors (q_min), high normalized beta...
Mr
Wayne M. Solomon
(USA)
09/10/2012, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
Recent experiments on DIII-D have demonstrated that advanced inductive discharges with high normalized fusion gain approaching levels consistent with ITER Q=10 operation can be accessed and sustained with very low amounts (~1 Nm) of externally driven torque. This level of torque is anticipated to drive a similar amount of rotation as the beams on ITER, via simple consideration of the scaling...
Mr
Charles E. Kessel
(USA)
09/10/2012, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
Alcator C-Mod is providing discharges that match several simultaneous parameters expected in ITER in the rampup, flattop and rampdown phases, and simulations of these discharges with time-dependent transport evolution codes. Discharges have been produced at both B = 5.4 T and 2.7 T, utilizing H-minority heating fundamental and 2nd harmonic, respectively. Discharges with rampup durations...
Mr
Josef Schweinzer
(Germany)
09/10/2012, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
‘Improved H-mode’ discharges in ASDEX Upgrade (AUG) are characterized by enhanced confinement factors, high beta and a q-profile with almost zero shear in the core of the plasma at q(0) around 1.
First attempts to reach high performance in the all-tungsten AUG relied on the observation that energy confinement was most improved when nitrogen (N) was puffed. In such plasmas the achieved...
Mr
Yunxing Ma
(MIT PSFC)
09/10/2012, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
Knowing the conditions for H-mode access is important for ITER high performance plasma operation. The experimental study carried out on Alcator C-Mod in support of this research primarily focused on (1) determining optimum global and local plasma conditions for promoting H-mode access, (2) characterizing plasma behaviors before L-H transition at low density, and (3) demonstrating a strong...
Mr
Young-Seok Park
(USA)
09/10/2012, 14:00
EXS - Magnetic Confinement Experiments: Stability
Poster
Initial H-mode operation of the KSTAR has been expanded to higher normalized beta, betaN, and lower plasma internal inductance, li, moving toward design target operation. As a key supporting device for ITER, an important goal for KSTAR is to produce physics understanding of MHD instabilities at long pulse with steady-state profiles, at high betaN and over a wide range of plasma rotation...
Mr
Gary L. Jackson
(USA)
09/10/2012, 14:00
EXS - Magnetic Confinement Experiments: Stability
Poster
Long duration plasmas, stable to m/n=2/1 tearing modes (TM), with an ITER similar shape and an ITER similar value of I_p/aB_T have been demonstrated in DIII-D, evolving to stationary conditions with the most stable operating point at beta_N approximately 2. Lower beta_N, corresponding to an ITER baseline scenario 2 value of 1.8, led to a higher probability of m/n=2/1 tearing modes modes, which...
Mr
Justin E. Barton
(USA)
09/10/2012, 14:00
EXS - Magnetic Confinement Experiments: Stability
Poster
Recent DIII-D experiments represent the first successful use of first-principles, model-based, full magnetic profile control in a tokamak. For ITER to be capable of operating in advanced tokamak operating regimes, characterized by a high fusion gain, good plasma confinement, magnetohydrodynamic stability, and a noninductively driven plasma current, for extended periods of time, several...
Mr
Roger Raman
(USA)
09/10/2012, 14:00
EXW - Magnetic Confinement Experiments: Wave–plasma interactions; current drive; heating; energetic particles
Poster
Transient Coaxial Helicity Injection (CHI) in the National Spherical Torus Experiment (NSTX) has generated toroidal current on closed flux surfaces without the use of the central solenoid. When induction from the solenoid was added, CHI initiated discharges in NSTX achieved 1 MA of plasma current using 65% of the solenoid flux of standard induction-only discharges. In addition, they have lower...
Mr
Yuichi Takase
(Japan)
09/10/2012, 14:00
EXW - Magnetic Confinement Experiments: Wave–plasma interactions; current drive; heating; energetic particles
Poster
To realize a compact spherical tokamak (ST) reactor, operation without the central solenoid must be demonstrated. In particular plasma current ramp-up from zero to a level required for fusion burn is crucial. Plasma initiation and current ramp-up in ST by waves in the lower-hybrid (LH) frequency range were demonstrated for the first time on TST-2. A combline antenna was used to inject RF power...
Mr
Takashi Mutoh
(Japan)
09/10/2012, 14:00
EXW - Magnetic Confinement Experiments: Wave–plasma interactions; current drive; heating; energetic particles
Poster
The steady state operation (SSO) of high-performance plasma in LHD [1] has progressed since the last IAEA conference by means of a newly installed ICH antenna (HAS antenna [2], HAnd Shake type) and an improved ECH system. HAS antenna could control the launched parallel wave number and heated a core plasma efficiently. The heating power of steady state ICH and ECH exceeded 1 MW and 500 kW,...
Mr
Jin Myung Park
(USA)
09/10/2012, 14:00
EXW - Magnetic Confinement Experiments: Wave–plasma interactions; current drive; heating; energetic particles
Poster
DIII-D experiments on neutral beam current drive (NBCD) using the new tilted beamline have clearly demonstrated off-axis NBCD in agreement with modeling. Two of the eight neutral beam sources have been modified for downward vertical steering to provide significant off-axis current drive for AT scenario development. For validation of off-axis NBCD physics, the local NBCD profile was measured in...
Mr
Hideki Zushi
(Riam Kyushu University)
09/10/2012, 14:00
EXW - Magnetic Confinement Experiments: Wave–plasma interactions; current drive; heating; energetic particles
Poster
ECW Start-up scenarios in QUEST: Non-inductive current start-up using ECW (f=8.2 GHz, P_{rf}\ll 140 kW, O-mode, N_\parallel 0<0.4) has been investigated from a view point of multiple ECR interaction, large up-shift and auto resonance condition (N_\parallel~1) in QUEST. Due to large up-shift of N_\parallel at R_{1ce}, ECCD with mildly relativistic electrons moving in the wave momentum...
Mr
Xianming SONG
(China)
09/10/2012, 14:00
EXW - Magnetic Confinement Experiments: Wave–plasma interactions; current drive; heating; energetic particles
Poster
ECRH pre-ionization and assisted startup is foreseen in ITER, because the electric field applied for ionization and ramp-up of plasma current is limited to a very low value about 0.3 V/m. Many data for ECRH pre-ionization and assisted startup have been obtained from C-Mod, ASDEX Upgrade, DIII-D, JT-60U, JET and KSTAR. This paper presents the experiment results in HL-2A Tokamak from 2010 to...
Mr
Syun'ichi SHIRAIWA
(USA)
09/10/2012, 14:00
EXW - Magnetic Confinement Experiments: Wave–plasma interactions; current drive; heating; energetic particles
Poster
Over 1 MW of RF power in the lower hybrid (LH) frequency range (4.6 GHz) has been injected into C-Mod plasmas. Fully non-inductive discharges were sustained for 2-3 current relaxation time with n_{e} = 0.5x10^{20} m^{-3}, I_p = 0.5 MA and B_T = 5.4 T. Sawteeth are completely suppressed and modestly reversed shear plasmas, with q_0 ~ 2 and q_{min} ~ 1.5, were obtained. CD efficiency is in the...
Mr
Sanjay Kulkarni
(India)
09/10/2012, 14:00
EXW - Magnetic Confinement Experiments: Wave–plasma interactions; current drive; heating; energetic particles
Poster
Here we report the pre-ionization experiments carried out in ICRF range using poloidal type fast wave antenna, and 200 kW RF system at 24.8 MHz frequency which corresponds to the second harmonic resonance layer at the center of the vacuum vessel of tokamak ADITYA at 0.825 T. The experiments are carried out in different phases like only RF plasma, RF plasma in presence of toroidal magnetic...
Mr
Denis Kalupin
(EU)
09/10/2012, 14:00
THC - Magnetic Confinement Theory and Modelling: Confinement
Poster
The “European Transport Solver” (ETS) is the new modular package for scenario simulations developed within the EFDA Integrated Tokamak Modelling (ITM) Task Force. It solves 1-D transport equations to which the geometry (2-D equilibrium), the transport coefficients and the sources are provided by stand alone modules coupled in a self consistent way to the transport solver through generalized...
Mr
Uri Shumlak
(USA)
09/10/2012, 14:00
THC - Magnetic Confinement Theory and Modelling: Confinement
Poster
Highlights of recent progress in the Plasma Science and Innovation (PSI) Center include adding reacting neutrals in the MHD model, providing capability for CAD description to grid generation to MHD simulation, incorporating energetic particles in extended MHD modeling, simulating 3D physics with Hall MHD, such as rotating magnetic field (RMF) current drive and inductive asymmetric current...
Mr
Gerardo Giruzzi
(France)
09/10/2012, 14:00
THC - Magnetic Confinement Theory and Modelling: Confinement
Poster
JT-60SA will be at the forefront of the international fusion programme for many years, both before and during the D-T phase of the ITER operation. The preparation of its scientific programme is now progressing in the framework of a Japan-EU collaboration and integrate advances coming both from experiments on other tokamaks and theoretical developments. As for ITER and DEMO, integrated...
Mr
Harry Mynick
(USA)
09/10/2012, 14:00
THC - Magnetic Confinement Theory and Modelling: Confinement
Poster
A method[1,2] has recently been developed for evolving toroidal configurations to ones with reduced turbulent transport, using the STELLOPT optimization code and the GENE gyrokinetic code. The potential for this method is now being explored and extended. The growing body of results has found that the effectiveness of the current “proxy” figure of merit Qprox used by STELLOPT to estimate...
Mr
Xavier LITAUDON
(France)
09/10/2012, 14:00
THC - Magnetic Confinement Theory and Modelling: Confinement
Poster
An attractive operating scenario for ITER has recently emerged that combines long plasma duration similar to the steady-state scenario, together with the reliability of the reference H-mode regime: the so-called ’hybrid’ scenario. Worldwide a significant experimental effort has been devoted to explore the operating space in present day tokamaks. This paper is an overview of the recent European...
Mr
Florin Spineanu
(Romania)
09/10/2012, 14:00
THC - Magnetic Confinement Theory and Modelling: Confinement
Poster
Mixed regimes consisting of coexistence large scale flows (H-mode, Internal Transport Barriers) and turbulence are expected to be the current state in ITER. The rotation, either spontaneous or induced, will play a major role in the quality of the confinment. We investigate the influence of the poloidal rotation on the toroidal flow. The efficiency of the sheared poloidal rotation to control...
Mr
Arnold Kritz
(USA)
09/10/2012, 14:00
THC - Magnetic Confinement Theory and Modelling: Confinement
Poster
Previous studies of ITER steady state and hybrid scenarios [1,2] are extended to studies of ITER ELMy H-mode 15 MA scenarios. Results are obtained using the PTRANSP predictive integrated modeling code with time evolved boundary conditions and the plasma shape provided by the Tokamak Simulation Code (TSC). Current is ramped to 15 MA during first 100 sec and the central density is ramped to...
Ms
Lu Wang
(Republic of Korea)
09/10/2012, 14:00
THC - Magnetic Confinement Theory and Modelling: Confinement
Poster
We present new results in the theory of non-diffusive heat transport, with special emphasis on electron thermal transport. Two foci of this paper are a) the theory of the convective energy velocity (i.e. heat pinch) for both electrons and ions [1], and b) the theory of collisionless electron-ion energy coupling [2]. Both these topics are important for ITER, since in a burning plasma, alpha...
Mr
Daniel Carmody
(USA)
09/10/2012, 14:00
THC - Magnetic Confinement Theory and Modelling: Confinement
Poster
Improved confinement scenarios in RFP plasmas that reduce global tearing modes are expected to lead to plasmas where confinement is limited by microturbulence driven by gradients of pressure, density, and temperature. Because enhanced confinement regimes in MST yield temperature profiles with core gradients near the critical threshold for temperature-gradient driven instability, a linear...
Mr
Vladimir Leonov
(Russian Federation)
09/10/2012, 14:00
THC - Magnetic Confinement Theory and Modelling: Confinement
Poster
At the development of plasma transport models it is very important to have the asymptotic transitions to the cases when transport coefficients are well described by some first principle based theories. For the ion component of tokamak plasma this is a transition to results of the neoclassical theory (in Ohmically heated high density discharges). Another stable opinion has been formed in...
Mr
Ozgur Gurcan
(LPP/Ecole Polytechnique/CNRS)
09/10/2012, 14:00
THC - Magnetic Confinement Theory and Modelling: Confinement
Poster
Nonlocality, which may manifest itself as a breaking of the favorable gyro-Bohm scaling of transport via phenomena such as avalanches or turbulence spreading and is an important threat to ITER operation has been considered and observed to various extents in simulations and experiments. Understanding of its details, is an essential challange for the transport community. Here, we present some...
Mr
Tariq Rafiq
(USA)
09/10/2012, 14:00
THC - Magnetic Confinement Theory and Modelling: Confinement
Poster
The MMM7.1 anomalous transport module, recently installed in the PTRANSP code, is used to compute thermal, particle and toroidal angular momentum transport. The new MMM7.1 is documented and organized as a standalone module, which fully complies with the NTCC standards. The new transport module can be used with a standalone driver as well as within the integrated PTRANSP code and in other...
Mr
Mitsuru Honda
(Japan)
09/10/2012, 14:00
THC - Magnetic Confinement Theory and Modelling: Confinement
Poster
A toroidal momentum equation solver newly implemented in TOPICS calculates a temporal variation of a total toroidal momentum with an external torque input by OFMC. A solid scheme that can calculate parallel, poloidal and toroidal flows, and thus the radial electric field E_r is developed using the Matrix Inversion method. The coupling of the solver and the scheme with the aid of OFMC provides...
Mr
Klaus Schoepf
(Austria)
09/10/2012, 14:00
THC - Magnetic Confinement Theory and Modelling: Confinement
Poster
The paper evaluates the influence of fusion alphas on burning plasmas in future tokamak reactors. In comparison to the relatively weak effect of charged fusion products (CFPs) in today’s devices, the substantially enhanced fusion power in burning tokamak plasmas may bring on a significant impact of CFPs on the equilibrium and bulk plasma parameters. Based on 3D Fokker-Planck modelling of DT...
Ms
Susanna Cappello
(Italy)
09/10/2012, 14:00
THC - Magnetic Confinement Theory and Modelling: Confinement
Poster
We present the current status of research in nonlinear modeling studies developed about the RFX-mod experiment, where several pinch configurations can be compared ranging from the self-organized helical RFP, to circular Tokamak passing through Ultra Low q ones, thus providing a flexible experiment in view of a future validation stage for several modeling tools. We focus presently on 3D...
Mr
Henri Weisen
(EU)
09/10/2012, 14:00
THC - Magnetic Confinement Theory and Modelling: Confinement
Poster
A systematic comparison of theoretical predictions for momentum transport in JET with experimental results has provided detailed insight into the physics of momentum transport, in particular non-diffusive transport. For this project, 400 representative experimental samples, selected from an extensive JET profile database with more than 1000 experimental profiles obtained over the entire...
Mr
Dominique Escande
(France)
09/10/2012, 14:00
THC - Magnetic Confinement Theory and Modelling: Confinement
Poster
Transport codes provide a classical way to infer the profile of transport coefficients in fusion plasmas: assuming given functionals for the transport coefficient profiles, the free parameters are iteratively adjusted to best reproduce the measurements. This work introduces a new technique, the matrix approach (MA), which avoids any a priori constraint of the profiles, and computes them by...
Mr
Robert Budny
(USA)
09/10/2012, 14:00
THC - Magnetic Confinement Theory and Modelling: Confinement
Poster
Toroidal momentum torques generating V_t (toroidal flow) affect ITB evolution and decay in TFTR, JT-60U and DIII-D, suggesting that momentum inputs could offer a means for controlling barrier dynamics. An important question is whether it is possible to produce and control an ITB with inputting toroidal momentum in a discharge. To explore the role of external inputs of toroidal momentum on the...
Mr
Clemente Angioni
(Germany)
09/10/2012, 14:00
THC - Magnetic Confinement Theory and Modelling: Confinement
Poster
The understanding of impurity transport from the wall to the center of the plasma and the identification of reliable methods to control central impurity accumulation are essential elements toward the achievement of practical fusion energy. A combination of theoretical and experimental research is required to identify the physical mechanisms from the theoretical standpoint, and to validate...
Mr
Shinichiro Toda
(Japan)
09/10/2012, 14:00
THC - Magnetic Confinement Theory and Modelling: Confinement
Poster
The formation mechanism of transport barriers is important issue to realize improved confinement modes in toroidal plasmas. In helical plasmas, two kinds of the oscillation for the plasma quantities are experimentally observed. Firstly, the limit cycle phenomena in the temporal evolution of the electrostatic potential, namely the electric pulsation, have been observed in the core region....
Mr
Akihiro Ishizawa
(Japan)
09/10/2012, 14:00
THC - Magnetic Confinement Theory and Modelling: Confinement
Poster
Turbulent transport in high-beta toroidal plasmas is investigated by means of a newly developed simulation code solving electromagnetic gyrokinetic equations combined with gyro-fluid equations for electrons. The new code allows simulations of turbulent transport at high-beta with smaller computational cost and less numerical difficulty than solving gyrokinetic equations for both electrons and...
Mr
Shinsuke Satake
(Japan)
09/10/2012, 14:00
THC - Magnetic Confinement Theory and Modelling: Confinement
Poster
Effect of magnetic perturbations on neoclassical toroidal viscosity (NTV) in tokamaks is investigated by using a drift-kinetic delta-f simulation code, FORTEC-3D. The effect of magnetic perturbation on plasma transport and rotation is one of the important issues in recent tokamak experiments and forthcoming ITER project, in which the resonant magnetic perturbation (RMP) applied externally is a...
Ms
Gloria Falchetto
(France)
09/10/2012, 14:00
THC - Magnetic Confinement Theory and Modelling: Confinement
Poster
The achievements and first physics results are presented of the European Integrated Tokamak Modelling Task Force (EFDA ITM-TF) effort, aiming at providing a standardized platform and an integrated modelling suite of validated numerical codes, for the simulation and prediction of a complete plasma discharge in any tokamak.
The framework developed by the ITM-TF, based on a generic...
Mr
Bruno Coppi
(USA)
09/10/2012, 14:00
THC - Magnetic Confinement Theory and Modelling: Confinement
Poster
A unified theory [1, 2] has been developed for the modes that are excited at the edge of the plasma column and are an important signature of the advanced confinement regimes in which magnetically confined plasmas can be driven. In particular the so-called EDA H-Regime, the Elmy H-Regime and the I-Regime are considered and the modes that are identified theoretically have characteristics that...
Mr
Kimin Kim
(USA)
09/10/2012, 14:00
THC - Magnetic Confinement Theory and Modelling: Confinement
Poster
Non-axisymmetric magnetic perturbations can fundamentally change neoclassical transport in tokamaks by distorting particle orbits on deformed or broken flux surfaces. Understanding transport under non-axisymmetric magnetic perturbations is a critical issue for ITER and future fusion devices where non-axisymmetric perturbations are potentially important control elements to actively stabilize...
Mr
J. Julio E. Herrera-Velazquez
(Mexico)
09/10/2012, 14:00
THC - Magnetic Confinement Theory and Modelling: Confinement
Poster
We show how the outer magnetic surfaces can be broken up in a spherical tokamak, by breaking the axisymmetry using an inner tilted coil. The configuration chosen for this work is that of the MEDUSA small spherical tokamak, a small glass chamber device, which allows the introduction of such a coil. The simulation is carried out with the 3D-MAPTOR code developed by the authors. Given an initial...
Mr
Diego del-Castillo-Negrete
(Fusion Energy Division. Oak Ridge National Laboratory)
09/10/2012, 14:00
THC - Magnetic Confinement Theory and Modelling: Confinement
Poster
Understanding heat transport in magnetized plasmas is a problem of fundamental interest in controlled fusion. Three issues make this problem particularly difficult: (i) The extreme anisotropy between the parallel (i.e., along the magnetic field), EMBED Equation.3 , and the perpendicular, EMBED Equation.3 conductivities; (ii) magnetic field lines chaos which in general precludes the...
Mr
Mirko Salewski
(Denmark)
09/10/2012, 14:00
THW - Magnetic Confinement Theory and Modelling: Wave–plasma interactions; current drive; heating; energetic particles
Poster
Collective Thomson scattering (CTS) and fast-ion D-alpha(FIDA) diagnostics measure 1D functions of the 2D fast-ion velocity distribution functions in magnetically confined plasmas. A single such 1D measurement is usually not sufficient to build accurate tomographies of 2D anisotropic fast-ion velocity distribution functions. But we can compute tomographies from several simultaneous 1D CTS and...
