First measurements on the core and edge isotope composition using the JET isotope separator neutral particle analyser

Bettella, D.; Murari, A.; Stamp, M.; Testa, D.

doi:10.1088/0741-3335/45/10/004

Cited by 6 publications

(3 citation statements)

References 19 publications

(32 reference statements)

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“…, only depends on N (since knowledge of r RES , hence q RES , and the actual measurement of N fully determines M) and can be obtained on a set of reference discharges. Indeed, earlier measurements of A EFF in JET using AE spectroscopy of low = N 1 modes for discharges with effectively an identical magnetic configuration have been proven to agree very well with the data obtained using the low-energy neutral particle analyser (NPA) and the charge-exchange (CX) diagnostic systems [1,5,6].…”

Section: Measurements Of the Radial Profile Of The Plasma Isotopic Co...supporting

confidence: 55%

Measurements of the radial profile of the plasma isotopic composition in JET plasmas using Alfvén eigenmodes

Testa¹,

Blanchard²,

Panis³

et al. 2015

Nucl. Fusion

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The measurement of the plasma isotopic composition is necessary in future burning plasma devices such as ITER and DEMO as a tool for optimizing the deuterium/tritium (DT) fusion performance. This paper reports on the results of experiments performed on the JET tokamak where toroidal Alfvén eigenmodes (TAEs) with toroidal mode number (N) up to N 12 = were actively driven with a set of in-vessel antennas, and were then used to infer the value of the plasma isotopic composition at different radial positions. A novel and important result with respect to previous work on JET is that by correctly including the effect of plasma impurities in the calculation of the Alfvén frequency, through its dependence on the plasma mass, it has become now possible to distinguish plasmas with different majority ion species but with the same charge-to-mass ratio, notably majority deuterium and helium4 plasmas. Furthermore, and combined with modelling of AEs in JET discharges, these experimental results indicate that a diagnostic system based on the detection of AEs with different toroidal mode numbers and at different frequencies, could provide profile measurements of the plasma isotopic composition in future burning plasma devices such as ITER and DEMO.

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Section: Measurements Of the Radial Profile Of The Plasma Isotopic Co...supporting

confidence: 55%

Measurements of the radial profile of the plasma isotopic composition in JET plasmas using Alfvén eigenmodes

Testa¹,

Blanchard²,

Panis³

et al. 2015

Nucl. Fusion

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show abstract

“…protons, deuterons and tritons allows potentially the measurement of local fuel mixture ratios in the confined plasma area [117]. Alternatively, methods based on experimental NPA data have been described recently which lead to local D/T ratios [118].…”

Section: Measurements Of Impuritiesmentioning

confidence: 99%

Chapter 7: Diagnostics

et al. 2007

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In order to support the operation of ITER and the planned experimental programme an extensive set of plasma and first wall measurements will be required. The number and type of required measurements will be similar to those made on the present-day large tokamaks while the specification of the measurements-time and spatial resolutions, etc-will in some cases be more stringent. Many of the measurements will be used in the real time control of the plasma driving a requirement for very high reliability in the systems (diagnostics) that provide the measurements.The implementation of diagnostic systems on ITER is a substantial challenge. Because of the harsh environment (high levels of neutron and gamma fluxes, neutron heating, particle bombardment) diagnostic system selection and design has to cope with a range of phenomena not previously encountered in diagnostic design. Extensive design and R&D is needed to prepare the systems. In some cases the environmental difficulties are so severe that new diagnostic techniques are required.The starting point in the development of diagnostics for ITER is to define the measurement requirements and develop their justification. It is necessary to include all the plasma parameters needed to support the basic and advanced operation (including active control) of the device, machine protection and also those needed to support the physics programme. Once the requirements are defined, the appropriate (combination of) diagnostic techniques can be selected and their implementation onto the tokamak can be developed. The selected list of diagnostics is an important guideline for identifying dedicated research and development needs in the area of ITER diagnostics.This paper gives a comprehensive overview of recent progress in the field of ITER diagnostics with emphasis on the implementation issues. After a discussion of the measurement requirements for plasma parameters in ITER and their justifications, recent progress in the field of diagnostics to measure a selected set of plasma parameters is presented. The integration of the various diagnostic systems onto the ITER tokamak is described. Generic research and development in the field of irradiation effects on materials and environmental effects on first mirrors are briefly presented. The paper ends with an assessment of the measurement capability for ITER and a forward of what will be gained from operation of the various diagnostic systems on ITER in preparation for the machines that will follow ITER. Performance assessment relative to requirements Design meets requirements S339 A.J.H. Donné et alPhysics Basis [7] and remains essentially the same. However, for ITER, the specific limits have changed. 2.1.2.Measurements needed for plasma control and evaluation. The measurements needed for plasma control and evaluation are naturally directly linked to the experimental programme, and particularly to the operating phase (i.e. H, D or D/T) and the operating scenario (H-mode, hybrid, etc). Since there is expected to be a phased introduction of po...

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“…Measurements of the hydrogen isotope composition of plasma by the charge-exchange neutral fluxes are used in the several experiments, including ASDEX Upgrade and JET [3][4][5]. The main advantage of the NPA diagnostics is that the neutral fluxes are directly related to the density of the corresponding ions in the plasma.…”

Section: Introductionmentioning

confidence: 99%

Assessment of neutral particle analysis abilities to measure the plasma hydrogen isotope composition in ITER burning scenarios

Afanasyev¹,

Mironov²,

Несеневич³

et al. 2013

Plasma Phys. Control. Fusion

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The main object of the neutral particle analysis (NPA) on ITER is to measure the hydrogen isotope composition of the plasma using measurements of the neutralized fluxes of the corresponding hydrogen ions. In burning scenarios the reliable on-line measurements of the tritium/deuterium (T/D) density ratio stands out as the most important application of the diagnostics. This paper presents the results of the error analysis of the NPA signals for 'official' ITER burning scenarios-inductive and steady state. The goal of the study is to find the range of values of T/D density ratio, where NPA measurements meet the ITER requirements specified for this parameter, i.e. 10% of accuracy and time resolution equal to 0.1 s. This analysis takes into account both the statistics of the particle counts detected by NPA and of the noise counts induced in NPA detectors by neutrons and gammas. The calibration errors and errors of the external plasma parameters, used in the interpretation of NPA data, are also accounted. The results of the study for low (20-200 keV) and high (200 keV-2 MeV) energy ranges of the D and T neutral fluxes are discussed. It was shown that in the inductive scenario NPA can provide the required accuracy of the T/D density ratio measurement if the plasma composition varies within 0.2-10 (edge measurements) and 0.15-10 (core measurements). In the steady-state scenario these ranges are 0.01-10 (edge measurements) and 0.07-7 (core measurements).

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First measurements on the core and edge isotope composition using the JET isotope separator neutral particle analyser

Cited by 6 publications

References 19 publications

Measurements of the radial profile of the plasma isotopic composition in JET plasmas using Alfvén eigenmodes

Measurements of the radial profile of the plasma isotopic composition in JET plasmas using Alfvén eigenmodes

Chapter 7: Diagnostics

Assessment of neutral particle analysis abilities to measure the plasma hydrogen isotope composition in ITER burning scenarios

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