Dr
Cami Collins
(General Atomics)
20/10/2016, 14:00
EXW - Magnetic Confinement Experiments: Wave–plasma interactions; current drive; heating; energetic particles
Poster
Recent experiments in the DIII-D tokamak show that many overlapping small-amplitude Alfvén eigenmodes (AEs) cause stiff fast-ion transport above a critical threshold. This result suggests that reduced models can be used to effectively predict alpha profiles, beam ion profiles, and losses to aid in the design of optimized scenarios for future burning plasma devices. Three key features of...
Dr
Ahmed Diallo
(PPPL)
20/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
The physical mechanism governing the L-H transition has been a long standing theoretical and experimental challenge. Understanding its trigger mechanism is critical for the operation of future fusion devices and ITER. This work is motivated by the need to test L-H transition models (e.g., predator-prey, and ExB flow suppression) and explore possible new L-H transition dynamics. This paper...
Dr
Alberto Loarte
(ITER Organization)
20/10/2016, 14:00
PPC - Plasma Overall Performance and Control
Poster
In order to evaluate if W accumulation is expected in ITER plasma conditions and whether the available heating systems can provide the degree of control required for stable H-mode operation we have applied integrated plasma models (ASTRA and JINTRAC) to a wide range of plasma conditions in ITER including confinement transients (i.e. L-H and H-L transitions). The studies find that, in agreement...
Dr
Andreas Bierwage
(National Institutes for Quantum and Radiological Science and Technology)
20/10/2016, 14:00
THW - Magnetic Confinement Theory and Modelling: Wave–plasma interactions; current drive; heating; energetic particles
Poster
Using the high-performance supercomputer Helios and advanced numerical methods, first-principle simulations of fast-ion-driven magnetohydrodynamic (MHD) modes have, for the first time, reproduced multiple cycles of so-called "Abrupt Large Events (ALE)" as observed in beam-driven high-beta JT-60 tokamak experiments. This is a major milestone because, unlike experiments, such simulations can...
Dr
Alessandro Biancalani
(Max-Planck-Institut für Plasmaphysik)
20/10/2016, 14:00
THW - Magnetic Confinement Theory and Modelling: Wave–plasma interactions; current drive; heating; energetic particles
Poster
Alfvén Eigenmodes (AE) are global instabilities excited by energetic particles (EP) in magnetic fusion devices. AE can redistribute the EP population across flux surfaces, making the plasma heating less effective, and leading to additional loads on the walls. The interplay of AEs and EPs is investigated by means of gyrokinetic particle-in-cell simulations, with a nonperturbative approach. The...
Dr
Robert Akers
(UKAEA)
20/10/2016, 14:00
THW - Magnetic Confinement Theory and Modelling: Wave–plasma interactions; current drive; heating; energetic particles
Poster
ITER will be the first tokamak to enter the burning plasma regime and approach ignition; plasma heating will be dominated by 3.5MeV fusion-born alpha-particles and 1MeV Heating Neutral Beam (HNB) injected deuterons (together with a fast particle population resulting from ICRH). In this paper we describe a new Monte Carlo code, designed to simulate fast ion behavior on ITER in the presence of...
Dr
Jon Hillesheim
(Culham Centre for Fusion Energy)
20/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
Unraveling the conditions that permit access to H-mode continues to be an unresolved physics issue for tokamaks. The scaling of the L-H transition power threshold, P_LH, to future devices has considerable uncertainty. Experiments have been performed in JET, with the ITER-like W/Be wall, to investigate the dependencies of P_LH and also to probe the underlying physics of the transition including...
Mr
Xavier Garbet
(CEA)
20/10/2016, 14:00
THC - Magnetic Confinement Theory and Modelling: Confinement
Poster
This paper investigates the interplay of neoclassical, turbulent and MHD processes, which are simultaneously at play when contributing to impurity transport. It is shown that these contributions are not additive, as assumed sometimes. The interaction between turbulence and neoclassical effects leads to less effective thermal screening, i.e. lowers the outward flux due to temperature gradient....
Dr
Manuel Garcia-Munoz
(Max-Planck Institute for Plasma Physics)
20/10/2016, 14:00
EXW - Magnetic Confinement Experiments: Wave–plasma interactions; current drive; heating; energetic particles
Poster
A joint experimental effort on the DIII-D and ASDEX Upgrade (AUG) tokamaks shows that fast-ion confinement is quite sensitive to both edge localized modes (ELMs) and the externally imposed magnetic perturbations (MPs) used to mitigate ELMs.
In DIII-D, the role of plasma response to extermanlly applied MPs, and its impact on fast ion loss, is studied by varying the relative phase between the...
Zheng Yan
(University of Wisconsin- Madison)
20/10/2016, 14:00
EXC - Magnetic Confinement Experiments: Confinement
Poster
Measurements of long wavelength (K_perp Rho_I<1) density fluctuation characteristics in the edge of both Deuterium (D) and Hydrogen (H) plasmas across the L-H transition on DIII-D demonstrate the existence of single or double bands of low-wavenumber turbulence observed near the edge of H and D plasmas, which are strongly correlated with the L to H-mode transition power threshold (P_LH) and can...
