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Journal Articles

Overview of high priority ITER diagnostic systems status

Walsh, M.*; Andrew, P.*; Barnsley, R.*; Bertalot, L.*; Boivin, R.*; Bora, D.*; Bouhamou, R.*; Ciattaglia, S.*; Costley, A. E.*; Counsell, G.*; et al.

Proceedings of 23rd IAEA Fusion Energy Conference (FEC 2010) (CD-ROM), 8 Pages, 2011/03

Journal Articles

Progress in the ITER physics basis, 7; Diagnostics

Donn$'e$, A. J. H.*; Costley, A. E.*; Barnsley, R.*; Bindslev, H.*; Boivin, R.*; Conway, G.*; Fisher, R.*; Giannella, R.*; Hartfuss, H.*; von Hellermann, M. G.*; et al.

Nuclear Fusion, 47(6), p.S337 - S384, 2007/06

 Times Cited Count:316 Percentile:78.95(Physics, Fluids & Plasmas)

no abstracts in English

Journal Articles

Progress in the ITER physics basis, 1; Overview and summary

Shimada, Michiya; Campbell, D. J.*; Mukhovatov, V.*; Fujiwara, Masami*; Kirneva, N.*; Lackner, K.*; Nagami, Masayuki; Pustovitov, V. D.*; Uckan, N.*; Wesley, J.*; et al.

Nuclear Fusion, 47(6), p.S1 - S17, 2007/06

 Times Cited Count:707 Percentile:99.94(Physics, Fluids & Plasmas)

The Progress in the ITER Physics Basis document is an update of the ITER Physics Basis (IPB), which was published in 1999. The IPB provided methodologies for projecting the performance of burning plasmas, developed largely through coordinated experimental, modeling and theoretical activities carried out on today's tokamaks (ITER Physics R&D). In the IPB, projections for ITER (1998 Design) were also presented. The IPB also pointed out some outstanding issues. These issues have been addressed by the International Tokamak Physics Activities (ITPA), which were initiated by the European Union, Japan, Russia and the U.S.A.. The new methodologies of projection and control developed through the ITPA are applied to ITER, which was redesigned under revised technical objectives, but will nonetheless meet the programmatic objective of providing an integrated demonstration of the scientific and technological feasibility of fusion energy.

Journal Articles

The Design and implementation of diagnostic systems on ITER

Costley, A. E.*; Walker, C. I.*; Bertalot, L.*; Barnsley, R.*; Itami, Kiyoshi; Sugie, Tatsuo; Vayakis, G.*

Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 8 Pages, 2007/03

In order to meet the needs for first wall and plasma measurements, ITER will require about 40 different diagnostic systems drawn from all the main generic diagnostic groups - magnetics, neutron systems, optical and microwave systems, spectroscopic, bolometric, probes, pressure gauges and gas analysers. The design and implementation is a major challenge because of the harsh environment in which many of the diagnostic components are located coupled with the restricted access and the need to meet stringent engineering requirements arising from the fact that ITER will be a nuclear device. It has stimulated an extensive design and R&D programme and the development of some novel approaches to diagnostic installation: for example, the use of plugs with custom modules at the upper and equatorial levels that serve both to support the diagnostic components and to provide the necessary shielding of the neutrons. The difficulties of implementation are summarized and the novel solutions described.

Journal Articles

High priority R&D topics in support of ITER diagnostic development

Donn$'e$, A. J. H.*; Costley, A. E.*; ITPA Topical Group on Diagnostics*

Proceedings of 21st IAEA Fusion Energy Conference (FEC 2006) (CD-ROM), 8 Pages, 2007/03

The development of diagnostics for ITER is a major challenge because of the harsh environment, strict engineering requirements and the need for high reliability in the measurements. A number of R&D tasks have been identified by the International Tokamak Physics Activity (ITPA) as "high priority" and form the focus of current work: (1) Review the requirements for measurements of the neutron/alpha particle source profile and assess possible methods of measurement, (2) Development of methods to measure the energy and density distribution of confined and escaping a-particles, (3) Determine any additional tests and measurements needed of the irradiation effects on candidate materials and sensors used for diagnostic construction, (4) Determine the life-time of plasma facing mirrors used in optical systems, (5) Develop the requirements for measurements of dust, and assess candidate techniques for the measurement of dust and erosion, (6) Assess the effects of radiation on magnetic coils used for measurements of the plasma equilibrium and support the development of new methods to measure steady state magnetic fields accurately in a nuclear environment. This paper will report on recent achievements in these tasks.

Journal Articles

Overview of goals and performance of ITER and strategy for plasma-wall interaction investigation

Shimada, Michiya; Costley, A. E.*; Federici, G.*; Ioki, Kimihiro*; Kukushkin, A. S.*; Mukhovatov, V.*; Polevoi, A. R.*; Sugihara, Masayoshi

Journal of Nuclear Materials, 337-339, p.808 - 815, 2005/03

 Times Cited Count:63 Percentile:96.36(Materials Science, Multidisciplinary)

ITER is an experimental fusion reactor for investigation and demonstration of burning plasmas, characterised of its heating dominated by alpha-particle heating. ITER is a major step from present devices and an indispensable step for fusion reactor development. ITER's success largely depends on the control of plasma-wall interactions(PWI), with power and particle fluxes and time scales one or two orders of magnitude larger than in present devices. The strategy for control of PWI includes the semi-closed divertor, strong fuelling and pumping, disruption and ELM control, replaceable plasma-facing materials and stepwise operation.

Journal Articles

Progress in physics basis and its impact on ITER

Shimada, Michiya; Campbell, D.*; Stambaugh, R.*; Polevoi, A. R.*; Mukhovatov, V.*; Asakura, Nobuyuki; Costley, A. E.*; Donn$'e$, A. J. H.*; Doyle, E. J.*; Federici, G.*; et al.

Proceedings of 20th IAEA Fusion Energy Conference (FEC 2004) (CD-ROM), 8 Pages, 2004/11

This paper summarises recent progress in the physics basis and its impact on the expected performance of ITER. Significant progress has been made in many outstanding issues and in the development of hybrid and steady state operation scenarios, leading to increased confidence of achieving ITER's goals. Experiments show that tailoring the current profile can improve confinement over the standard H-mode and allow an increase in beta up to the no-wall limit at safety factors $$sim$$ 4. Extrapolation to ITER suggests that at the reduced plasma current of $$sim$$ 12MA, high Q $$>$$ 10 and long pulse ($$>$$1000 s) operation is possible with benign ELMs. Analysis of disruption scenarios has been performed based on guidelines on current quench rates and halo currents, derived from the experimental database. With conservative assumptions, estimated electromagnetic forces on the in-vessel components are below the design target values, confirming the robustness of the ITER design against disruption forces.

Journal Articles

Toroidal interferometer/polarimeter density measurement system on ITER

Kondoh, Takashi; Costley, A. E.*; Sugie, Tatsuo; Kawano, Yasunori; Malaquias, A.*; Walker, C. I.*

Review of Scientific Instruments, 75(10), p.3420 - 3422, 2004/10

 Times Cited Count:23 Percentile:72.73(Instruments & Instrumentation)

In order to measure the line average electron density on ITER, a CO$$_{2}$$ laser interferometer/polarimeter system is being developed. The design of the interferometer/polarimeter is improved from the previous design, which uses CO$$_{2}$$ and CO laser, on the basis of experience gained with a dual CO$$_{2}$$ system on JT-60U in which good reliability was confirmed for both interferometry and polarimetry operation. The performance of the dual CO$$_{2}$$ laser meets requirements for ITER (accuracy; 1%, time resolution; 1 ms).

Journal Articles

Overview of physics basis for ITER

Mukhovatov, V.*; Shimada, Michiya; Chudnovskiy, A. N.*; Costley, A. E.*; Gribov, Y.*; Federici, G.*; Kardaun, O. J. F.*; Kukushkin, A. S.*; Polevoi, A. R.*; Pustovitov, V. D.*; et al.

Plasma Physics and Controlled Fusion, 45(12), p.235 - 252, 2003/12

 Times Cited Count:50 Percentile:80.98(Physics, Fluids & Plasmas)

ITER will be the first magnetic confinement device with burning DT plasma and fusion power of about 0.5 GW. During the past few years, new results have been obtained that substantiate the confidence in achieving Q $$>$$ 10 in ITER with inductive H-mode operation. These include achievement of a good H-mode confinement near the Greenwald density at high triangularity of the plasma cross section; improvements in theory-based confinement projections for the core plasma; improvement in helium ash removal due to the elastic collisions of He atoms with D/T ions in the divertor predicted by modelling; demonstration of feedback control of NTMs and resultant improvement in the achievable beta-values; better understanding of ELM physics and development of ELM mitigation techniques; and demonstration of mitigation of plasma disruptions. ITER will have a flexibility to operate also in steady state and intermediate (hybrid) regimes. The paper concentrates on inductively driven plasma performance and discusses requirements for steady-state operation in ITER.

Journal Articles

Spectroscopic diagnostics for ITER

Sugie, Tatsuo; Costley, A. E.*; Malaquias, A.*; Walker, C.*

Purazuma, Kaku Yugo Gakkai-Shi, 79(10), p.1051 - 1061, 2003/10

The main regions - the core, the edge, the scrape-off layer, and the divertor - will be probed by an extensive array of spectroscopic instrumentation covering the visible to X-ray wavelength range. Plasma parameters will be determined including impurity species/density/input-flux, ion temperature, He density, fueling ratio, plasma rotation, effective ionic charge and safety factor q. The measurements will be used for plasma control and in studies to understand and improve the performance of ITER. A diagnostic neutral beam (~100 keV) will be installed for Charge Exchange Recombination Spectroscopy. Motional Stark Effect measurements (for q profile) will be made using the heating beam (1 MeV). Diagnostic components, such as mirrors, windows, and optical fibers etc, mounted close to the plasma will experience higher levels of radiation due to neutron, gamma ray and particle irradiations than in present devices. Potentially their performance characteristics can be degraded and so the materials of the components have to be carefully selected and mitigating methods adopted where possible.

Journal Articles

Spectroscopic measurement system for ITER divertor plasma; Divertor impurity monitor

Sugie, Tatsuo; Costley, A. E.*; Malaquias, A.*; Medvedev, A.*; Walker, C.*

Proceedings of 30th EPS Conference on Controlled Fusion and Plasma Physics (CD-ROM), 4 Pages, 2003/07

The main functions of the Divertor Impurity Monitor are to measure the parameters of impurities and isotopes of hydrogen in the divertor plasmas by using spectroscopic techniques in the wavelength range of 200-1000 nm. This system will have three different types of spectrometers; a) Visible survey spectrometers for impurity species monitoring. b) Filter spectrometers for two-dimensional measurements of particle influxes. c) High dispersion spectrometers for measuring the ion temperature and the particle energy distribution. The divertor region will be observed from the divertor-, the equatorial- and the upper-port. Optical components, such as mirrors, windows etc, mounted close to the plasma will experience higher levels of radiation due to neutron, gamma ray and/or particle irradiations than in present devices. Therefore, the materials of the components have to be carefully selected and mitigating methods adopted where possible. In addition, in-situ and remote calibration methods for diagnostic systems, which will be installed in the strong radiation field, are absolutely essential.

Journal Articles

Prospects for $$alpha$$-particle diagnostics by CO$$_{2}$$ laser collective Thomson scattering in ITER

Kondoh, Takashi; Richards, R. K.*; Hutchinson, D. P.*; Sugie, Tatsuo; Costley, A. E.*; Miura, Yukitoshi; Lee, S.*

Proceedings of 30th EPS Conference on Controlled Fusion and Plasma Physics (CD-ROM), 4 Pages, 2003/07

In order to understand the behavior of alpha-particles which are the dominant heat source in a burning plasma, it is necessary to measure the spatial distribution of the number of the alpha-particles and their energy spectrum. A collective Thomson scattering (CTS) system based on a pulsed CO$$_{2}$$ laser is being developed and is under consideration for alpha-particle measurements on ITER. Heating beam ions (E = 1 MeV) are normally co-injected and have a similar velocity with alpha-particles in ITER. The CTS measurement can not, in general, distinguish beam ions and alpha-particles which have the same velocity. A vertical scattering geometry to distinguish between beam ions and alpha-particles is proposed. Calculations have shown that the vertically viewing CTS can resolve counter-travelling alphas without being masked by beam ions. Preliminary design of a beam line and a receiver system with the vertical scattering geometry has been developed. A proof-of-principle test on the CTS system using the JT-60U plasma is being conducted.

Journal Articles

Toroidal interferometer/polarimeter density measurement system for long pulse operation on ITER

Kondoh, Takashi; Kawano, Yasunori; Costley, A. E.*; Malaquias, A.*; Sugie, Tatsuo; Walker, C.*

Proceedings of 30th EPS Conference on Controlled Fusion and Plasma Physics (CD-ROM), 4 Pages, 2003/07

In order to measure line average electron density for long pulse operation on ITER, a CO$$_{2}$$ laser interferometer/polarimeter system has being selected. High reliability is necessary because the measurements will be used as a reference signal for real time control of the density during long plasma pulses. The design of the interferometer/polarimeter is improved from the previous design because of an input from experiences gained on JT-60U. A dual CO$$_{2}$$ laser interferometer/polarimeter was chosen in order to improve reliability. The proof-of-principle test of the dual CO$$_{2}$$ laser interferometer/polarimeter has been demonstrated and the system is operating routinely on JT-60U. Five tangential sight lines are designed near the midplane of ITER. The laser beams will be transmitted to the plasma through shielding labyrinths in an equatorial port and reflected by retroreflectors. Position of the laser beams will be remotely controlled by steering mirrors outside the port plug because the vacuum vessel of ITER will move due to change in temperature during long plasma pulses.

Journal Articles

Impact of irradiation effects on design solutions for ITER diagnostics

Yamamoto, Shin; Shikama, Tatsuo*; Belyakov, V.*; Farnum, E.*; Hodgson, E. R.*; Nishitani, Takeo; Orlinski, D.*; Zinkle, S.*; Kasai, Satoshi; Stott, P.*; et al.

Journal of Nuclear Materials, 283-287(1), p.60 - 69, 2000/12

 Times Cited Count:66 Percentile:96.45(Materials Science, Multidisciplinary)

no abstracts in English

Oral presentation

Scheme of in-situ sensitivity calibration for divertor impurity monitor in ITER

Sugie, Tatsuo; Costley, A. E.*; Ogawa, Hiroaki; Kasai, Satoshi; Walker, C.*

no journal, , 

The Divertor Impurity Monitor will use mirrors as the first optical element and these mirrors will potentially be subject to damage from impurity deposition and dust. Measures to reduce/eliminate the effects of these depositions are being developed. However, it will not be possible to prevent the degradation completely. Therefore, in-situ and remote calibration methods, which will have to be installed in the strong radiation field, are required. So far an in-situ calibration system using a retro-reflector, which is installed in front of the first mirror, has been designed. However, a small amount of the incident light goes back to the detector due to the asymmetric optics. To solve this problem, a method using a micro retro-reflector array instead of the retro-reflector is studied here. A standard light is set behind the bio-shield or in the diagnostic room and the light is applied to the micro retro-reflector array through the same optics which is used in the plasma measurement. The reflected light is measured with a detector to estimate the sensitivity change of the optics. The signal to noise ratio has been estimated under the assumption that the plasma facing first mirror is made of molybdenum and other mirrors are made of aluminum. In addition, we assume the use of a xenon lamp for the light source and a back-thinned type CCD for the detector. As a result, sufficient signal to noise ratio will be obtained by this calibration system in the wavelength range of 200 - 1000 nm.

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