This paper studies the effect of bundling groups of contiguous carbon and tungsten ionization stages on the calculated impurity screening. EDGE2D/EIRENE was used to calculate the charge state ...distribution in the SOL and the edge of the plasma core, which resulted from the puffing of either atomic carbon or tungsten at the JET outer mid-plane. The input parameters were constant for a number of code calculations where the only parameter changed was the number and/or charge states bundled in either carbon or tungsten. In this manner, the effect of bundling on the carbon or tungsten screening or fuelling efficiency was determined. For carbon and tungsten there was only a weak dependence upon the actual bundling scheme used.
The JET Intershot Analysis (Chain1) generates processed data following a pulse. Maintaining the pulse repetition rate is one of JET's key success factors, so performance of Chain1 is crucial. This ...paper will describe JET's experience of managing Chain1, including a description of the control system used to ensure the analysis chain runs as quickly as possible, and a discussion of JET's experience of integrating externally developed codes into a standard analysis framework.
The current Chain1 infrastructure was developed in 1999 and although reliable and efficient is starting to prove costly in terms of flexibility and extensibility to meet JET's current and future needs. For this reason JET is planning to re-implement the Chain1 system. The paper will outline the work done towards this aim, and present a model of the proposed new system. Finally, possible future steps towards an integrated data production chain for JET will be discussed, and the potential applicability to next generation fusion devices will be outlined.
Fusion Advanced Studies Torus (FAST) aims to contribute to the exploitation of ITER and to explore innovative DEMO technology. FAST has been designed to study, in an integrated scenario: (a) relevant ...plasma-wall interaction problems, with a large power load (
P/
R
∼
22
MW/m;
P/
R
2
∼
12
MW/m
2) and with a full metallic wall; (b) to tackle operational problems in regimes with relevant fusion parameters; (c) to investigate the non-linear dynamics of fast particles (alpha like) in burning plasmas. FAST will operate on a wide parameters range, namely in high performance H-mode (BT
∼
8.5
T; IP
∼
8
MA) as well as in advanced Tokamak operation up to full non-inductive current scenario (IP
∼
2
MA). The main heating is based on 30
MW ICRH, but the ports have been designed to allocate up to 20
MW of 1
MeV NNBI. Helium gas at 30
K is used for cooling of the full machine, a preliminary analysis shows the possibility of realizing FAST with a complete superconductor set of coils. An innovative active system is under development to reduce and to control the magnetic ripple. Tungsten (W) or liquid lithium (L–Li) has been chosen for the divertor material plates and the code EDGE2D has been used to optimize the divertor geometry.
The paper addresses basic features of non-axisymmetric edge transport induced in tokamaks by local limiters or external magnetic perturbations and in low-shear stellarators by the presence of edge ...magnetic islands. 3D simulations and, if available for comparison, experimental results are presented and discussed for three devices, ITER during start-up operation, TEXTOR-DED and W7-AS, having edge topologies totally different from each other. The modeling is performed with the EMC3/EIRENE code, which treats self-consistently plasma, neutral and impurity transport in a general 3D scrape-off layer (SOL) with arbitrarily complex geometry of magnetic configuration and plasma-facing components. Shown are code predictions of the power load on the ITER start-up limiters as well as modeling results on the transport in the TEXTOR-DED stochastic edge and on the physics of stable detachment in W7-AS. Experimental observations confirming the code simulations are referenced for both TEXTOR-DED and W7-AS, a direct comparison between modeling and experimental results is shown for W7-AS.
Experimental results from the dynamic ergodic divertor (DED) at TEXTOR are given, describing the complex structure of the edge plasma and the properties of the divertor as well as its influence on ...the plasma rotation.
Active control of edge localized modes (ELMs) by using static external magnetic perturbation fields with low toroidal mode number,
n, has been demonstrated for both, ITER baseline (
q
95
∼
3
) and ...high beta advanced tokamak scenarios at the JET tokamak. During the application of the low
n field the ELM frequency increased by a factor up to ∼4–5. Reduction in carbon erosion and ELM peak heat fluxes on the divertor target by roughly the same factor as the increase of the ELM frequency has been observed. The frequency of the mitigated ELMs using a low
n field is found to increase proportional to the total input heating power. Compensation of the density pump-out effect observed when the external low
n field is applied has been achieved by gas fueling in low triangularity plasmas.
At TEXTOR the dynamic ergodic divertor (DED) induces a stochastic edge layer by a resonant magnetic perturbation to control heat and particle exhaust. In this paper the characterization of its ...generic transport properties is described. The radial and poloidal distribution of electron density and temperature is analyzed accompanied by observations of the particle flux to the DED target. These experimental results are compared to the calculated magnetic topology and to results from EMC3/EIRENE modeling. Thereby, the existence of two poloidally separated transport domains is demonstrated: laminar flux tubes are dominated by parallel transport to the DED target – they act analogous to a classical scrape-off layer. In contrast, the adjacent ergodic domains show stochastic transport characteristics with enhanced radial transport.
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