Overview of JET results

Paméla, J.; Ongena, J.; Contributors, Jet

doi:10.1088/0029-5515/45/10/s06

Cited by 27 publications

(24 citation statements)

References 86 publications

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“…The remainder of the paper reports progress and achievements on topics of a more technical nature: studies of the ELMs using fast RF measurements, experimental demonstration of a new ELM-tolerant antenna matching scheme, and the technical 1 Major radius R 0 ≈3m, horizontal plasma minor radius ≈1m, maximum plasma elongation ≈2, ITERrelevant plasma triangularities, maximum toroidal field 4T at the magnetic axis, maximum current 5MA in the present divertor configuration. 6 enhancements under implementation on the JET ICRF system, themselves likewise strongly driven by the preparation for ITER.…”

Section: Introductionmentioning

confidence: 99%

Expanding the operating space of ICRF on JET with a view to ITER

et al. 2006

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This paper reports on ITER-relevant ICRF physics investigated on JET in 2003 and early 2004.Minority heating of helium three in hydrogen plasmas -( 3 He)H -was systematically explored by varying the 3 He concentration and the toroidal phasing of the antenna arrays. The best heating performance (a maximum electron temperature of 6.2keV with 5MW of ICRF power) was obtained with a preferential wave launch in the direction of the plasma current. A clear experimental demonstration was made of the sharp and reproducible transition to the mode conversion heating regime when the 3 He concentration increases above ~2%. In the latter regime the best heating performance (a maximum electron temperature of 8keV with 5MW of ICRF power) was achieved with dipole array phasing, i.e. a symmetric antenna power spectrum. Minority heating of deuterium in hydrogen plasmas -(D)H -was also investigated but was found inaccessible, because this scenario is too sensitive to impurity ions with Z/A=1/2 such as C 6+ , small amounts of which directly lead into the mode conversion regime. Minority heating of up to 3% of tritium in deuterium plasmas was systematically investigated during the JET Trace Tritium experimental campaign (TTE). This required operating JET at its highest possible magnetic field (3.9 to 4T) and the ICRF system at its lowest frequency (23MHz). The interest of this scenario for ICRF heating at these low concentrations and its efficiency at boosting the suprathermal neutron yield were confirmed, and the measured neutron and gammay ray spectra permit interesting comparisons with advanced ICRF code simulations.Investigations of finite Larmor radius effects on the RF-induced high-energy tails during second harmonic (ω=2 ω c ) heating of a hydrogen minority in D plasmas clearly demonstrated a strong decrease of the RF diffusion coefficient at proton energies ~1MeV, in agreement with theoretical 4 expectations. Fast wave heating and current drive experiments in deuterium plasmas showed effective direct electron heating with dipole phasing of the antennas, but only small changes of the central plasma current density were observed with the directive phasings, in particular at low single pass damping. New investigations of the heating efficiency of ICRF antennas confirmed its strong dependence on the parallel wavenumber spectrum. Advances i n topics of a more technological nature are also summarized: ELM studies using fast RF measurements, the successful experimental demonstration of a new ELM-tolerant antenna matching scheme, and technical enhancements planned on the JET ICRF system for 2006, themselves equally strongly driven by the preparation for ITER.5

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Section: Introductionmentioning

confidence: 99%

Expanding the operating space of ICRF on JET with a view to ITER

et al. 2006

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“…• Fusion: this very long term R&D effort should be kept in close collaboration with international programs with very fundamental research aspects [18], but also a need for successful demonstration steps and a growing attention for plant predesign • Solar thermal : the main areas of research are advanced concentration with high temperature storage and processes and for solar photovoltaic (with or without concentration, flexible or not, on transparent support or not, etc. ) • Geothermal : research is required on efficient low temperature conversion cycles and the development of hot dry rock technologies (crack generation, sealing technologies and anti-deposit technologies, .…”

Section: Energy Conversionmentioning

confidence: 99%

Energy in the perspective of the sustainable development: The 2000W society challenge

Maréchal

Favrat

Jochem

2005

Resources, Conservation and Recycling

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As energy plays a central role in the world development, it represents as well a major challenge for sustainable development. Today, more than 80 % of the primary energy consumption is based on fossil fuels and the share is likely to remain high in the future. Even if technology developments will reduce the specific consumption, the world energy demand is likely to increase in line with its population. Energy and material efficiency and the integration of the renewable resources will therefore have to play a major role for sustainable development. The challenge concerns not only the technologies at the conversion and useful energy level, but also the energy management and infrastructures. The 2000 W per capita society initiative launched by the Board of the Swiss Institutes of Technology targets the identification of the major technological breakthroughs to reduce the per capita primary energy use of Switzerland by two thirds within five decades. This study examined the energy saving potentials in the complete conversion chain "from primary energy to energy services" in the main sectors of economy: buildings, transport and industry. The report highlights the possible benefits which could be obtained from new materials, new technologies and an intensification of product and capital use. The systems integration appeared to be of prime importance in order to valorise the exergy potentials of the energy resources. The report emphasizes the political responsibility of developing the enabling society infrastructure: not only for the energy distribution (electrical, gas or heating networks) but also for the information technology, the appropriate regulations, the education and for the necessary integration of the lifetimes of the manufactured artefacts in the pathway to the 2000 W per capita Society.

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“…With growing tokamak size the ELMs become a severe threat for the in-vessel components. For the largest present day machines like JET, ELMs can cause target ablation in the divertor; 7 for ITER the undamped intrinsic ELMs would most probably result in a fatally fast erosion of the divertor plates when operating in the foreseen operational scenario. 8 Hence, strategies are under investigation aiming to abandon or at least mitigate the ELM impact.…”

Section: Introductionmentioning

confidence: 99%

Cryogenic pellet launcher adapted for controlling of tokamak plasma edge instabilities

Lang

Cierpka

Harhausen

et al. 2007

Review of Scientific Instruments

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One of the main challenges posed recently on pellet launcher systems in fusion-oriented plasma physics is the control of the plasma edge region. Strong energy bursts ejected from the plasma due to edge localized modes ͑ELMs͒ can form a severe threat for in-vessel components but can be mitigated by sufficiently frequent triggering of the underlying instabilities using hydrogen isotope pellet injection. However, pellet injection systems developed mainly for the task of ELM control, keeping the unwanted pellet fueling minimized, are still missing. Here, we report on a novel system developed under the premise of its suitability for control and mitigation of plasma edge instabilities. The system is based on the blower gun principle and is capable of combining high repetition rates up to 143 Hz with low pellet velocities. Thus, the flexibility of the accessible injection geometry can be maximized and the pellet size kept low. As a result the new system allows for an enhancement in the tokamak operation as well as for more sophisticated experiments investigating the underlying physics of the plasma edge instabilities. This article reports on the design of the new system, its main operational characteristics as determined in extensive test bed runs, and also its first test at the tokamak experiment ASDEX Upgrade.

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Overview of JET results

Cited by 27 publications

References 86 publications

Expanding the operating space of ICRF on JET with a view to ITER

Expanding the operating space of ICRF on JET with a view to ITER

Energy in the perspective of the sustainable development: The 2000W society challenge

Cryogenic pellet launcher adapted for controlling of tokamak plasma edge instabilities

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