Conveners
Poster session: Poster Session 1 and coffee break
- Franco Alladio (ENEA-FSN-Fusphy)
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Lorenzo Valvo (Centre de Physique Theorique CPT, Aix-Marseille University)poster
Guiding Centre theory has been developed to describe the dynamics of charged particles subject to the Lorentz force. In the context of fusion theory, it is used in numerical simulations to find approximate trajectories of particles in an external field which can be locally approximated by a straight uniform one, but also the collective effect of an ensemble of such particles as a part of a...
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Jeong-hun Yang (PPPL)poster
Tearing mode (TM) instabilities are analyzed experimentally in NSTX plasmas. 2-D ultra-soft X-ray measurements are used to infer the magnetic island width, phase and radial location, by fitting the simulated perturbed emissivity to the measured one. Fitted results are further complemented by the data, on mode frequency and number from Mirnov coils and on mode frequency and location from plasma...
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Mr Wenbin Liu (Tsinghua University)poster
Recent flux-driven gyrokinetic computational modeling and theory suggested the existence of an E×B staircase in the plasma core consisting of a series of m/n=0/0 E×B shear layers formed at different plasma minor radii. These layers then act as semi-permeable transport barriers and thus regulate the background gradients. Experimental work in TORE-SUPRA shows that the turbulent radial...
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Mr Binbin Wang (Tsinghua University)poster
Experiments have been performed on the MAST spherical tokamak that the gas puffing in the high-field side (HFS) will improve the plasma confinement. Considering the limited space and short discharge duration of SUNIST spherical tokamak, a fast and compact valve is necessary for gas injection. A new fast magnetic valve has been developed for the gas injection research on SUNIST. The open state...
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Devon Battaglia (PPPL), R.E. Bell (Princeton Plasma Physics Lab), Dr Stefan Gerhardt (Princeton Plasma Physics Laboratory), Dr Walter Guttenfelder (Princeton Plasma Physics Laboratory), Stanley Kaye (PPPL), Dr Rajesh Maingi (Princeton Plasma Physics Laboratory)poster
The largest normalized energy confinement attained over a confinement time on NSTX (H98 > 1.5) was achieved in the ELM-free Enhanced Pedestal (EP) H-mode regime [1-3] that features a wide pedestal with a significant increase in the edge carbon temperature and rotation gradients. These discharges achieve improved energy and momentum confinement with a beneficial decrease in the impurity...
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Mr Lee Kihyun (Seoul National Univertisy)poster
The neutral beam injection (NBI) system commissioning and first beam heating experiments in Versatile Experiment Spherical Torus (VEST) have been carried out. The ion beam power of ~0.6MW was successfully extracted from the ion source through commissioning. The ion source consists of arc plasma source and multi-aperture accelerator assembly which is developed by Korea Atomic Energy Research...
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Luis Araya-Solano (Costa Rica Institute of Technology)poster
The low aspect ratio spherical tokamak MEDUSA (Madison Educational Small Aspect Ratio Tokamak) built by the University of Wisconsin-Madison (USA) and donated to $\textit{Instituto Tecnológico de Costa Rica}$ is currently being re-commissioned at $\textit{PlasmaTEC}$. The main characteristics of this device (renamed MEDUSA-CR) are: plasma major radius $R_0$ < 0.14 m, plasma minor radius a <...
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Mr SHOUZHI WANG (TSINGHUA UNIVERSITY)poster
The electron Bernstein wave (EBW) is a promising method for heating and current drive in overdense plasmas. To evaluate spontaneous conditions for EBW heating on SUNIST spherical tokamak, EBW emissions in the frequency of 3 to 6 GHz, corresponding to the fundamental and second harmonic in low toroidal field (0.1 T) discharge, were measured and analyzed. Emissions were collected by an in-vacuum...
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Mr Seongcheol Kim (Seoul National University)poster
Recent research on MHD instabilities in VEST (Versatile Experiment Spherical Torus) has focused on the tearing mode during current ramp up phase and the so-called IRE (Internal Reconnection Event) known to occur frequently in spherical torus. The tearing mode at the current ramp-up phase, known to be related to the hollow current density profile with fast ramp-up rate, seems to be suppressed...
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Dr R. Maingiposter
Projected divertor heat flux footprints from Eich1 and Goldston2 scalings for next step devices is in the range of 1-2 mm, with unmitigated peak heat fluxes of several hundred MW/m2. However there may be meaningful deviations from these scalings for spherical tokamaks, e.g. NSTX3. At full plasma current and heating power, nonetheless, H-mode discharges in NSTX-U4 are projected to have midplane...
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Dr Stanley Kaye (Princeton Plasma Physics Laboratory)poster
The eight major scope items in the NSTX-U Recovery Project include: (1) six redesigned inner PF coils, (2) redesigned upper and lower polar region structures, (3) redesigned select plasma facing components, (4) improved bake-out, (5) additional component stress/strain trending instrumentation, (6) enhanced test cell shielding, (7) implementation of the accelerator safety order, and (8)...
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Dr Kengoh KURODA (Kyushu University)poster
Transient Coaxial Helicity Injection (T-CHI) current start-up by using a simple configuration electrode installed in QUEST has been tested on a collaborative research project between University of Washington, Princeton Plasma Physics Laboratory (PPPL) and Kyushu University [1]. T-CHI has been developed as a solenoid-free plasma start-up method in HIT-II and NSTX [2,3]. The conventional T-CHI...
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Mr Yuhang Luo (Department of Engineering Physics, Tsinghua University, Beijing 100084, China)poster
Helicity injection is a non-inductive current drive method used in the startup of Spherical Torus and Spheromak. The mechanism of current drive is explained by Taylor relaxation by which the plasma will relax into the Taylor state. The most important feature of Taylor state is that $\lambda\equiv{j\cdot B}/{\vert B^2\vert}$ is constant all over the plasma. However, the research of how the...
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