ITER neutral beam system

Mondino, P.L.; Bayetti, P.; Pietro, E. Di; Hemsworth, R.; Iida, H.; Inoue, T.; Ioki, K.; Johnson, G.; Krylov, A.; Kulygin, V. M.; Massmann, P.; Miyamoto, K.; Okumura, Y.; Panasenkov, A. A.; Santoro, R.T.; Sironi, M.; Utin, Y.; Watanabe, K.; Yamada, Masakazu

doi:10.1088/0029-5515/40/3y/309

Cited by 28 publications

(7 citation statements)

References 3 publications

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“…At ITER an important problem is that the momentum transfer from a high energy beam decreases with increasing energy (assuming the same power). Since an energy of 1 MeV is envisaged [46], a decrease in the momentum input by a factor of ≈3 could lead to a rotation speed considerably lower than in JET. In addition it follows from the global momentum balance [47] that this speed scales inversely with the plasma volume which is roughly 10 times larger than that of JET.…”

Section: Conclusion and Discussionmentioning

confidence: 99%

Interaction of plasma rotation and resonant magnetic perturbation fields in tokamaks

Nicolai¹,

Daybelge²,

Lehnen³

et al. 2008

Nucl. Fusion

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The interaction between plasma rotation and perturbation fields is described by the ambipolarity constraint and the parallel momentum balance, both emanating from the revisited neoclassical theory, and the electrodynamical screening of the resonant perturbation field at the singular surfaces. This screening depends mainly on the slip between the rotating plasma and the resonant field. The neoclassical theory, valid in the collision dominated regime and accounting for gyro-viscosity, includes arbitrary plasma cross-sections, anomalous viscosity, ponderomotive forces, neutral beam injection (NBI), pressure anisotropization and a momentum source due to ergodicity which has a considerable impact on the plasma rotation as demonstrated in TEXTOR.To estimate the influence of the perturbation coils on the plasma rotation, the radial magnetic field (proportional to the helical flux function) is Fourier analysed (using 'intrinsic' coordinates) and the total field is used for field line tracing thus obtaining the ponderomotive momentum input and the extension e of the ergodic layer at the edge. Both procedures account for the full plasma geometry. e is assumed to be independent of the rotational state because of the boundary condition V t = 0. In a second step the obtained velocity profiles are used to compute the screening at the singular layers and thus the reduction of the island width due to plasma rotation.The main results can be summarized as follows.Using in the case of TEXTOR shot #94092 the diffusion coefficient D M = 2 × 10 −6 m (typical for the 12/4 configuration) the observed increase in v t by v t ≈ 5 km s −1 can be reproduced. Inside the plasma the slip prevents any influence of the ponderomotive forces, thus yielding a constant increase in the v t (r)-profile by v t .Assuming in the case of the error field correction coils (n = 1) of JET the current I hel = 30 kA and using for the plasma background the data of shot #67951 in the static case, an ergodized layer ( e (n = 1) ≈ 20 cm in the vicinity of the unperturbed x-point) and large m = 2, m = 3 (n = 1) islands (W m=2,n=1 = 10 cm) are obtained. In the n = 2 configuration the analogous parameters are e (n = 2) ≈ 18 cm and W m=2,n=2 = 4 cm i.e. e stays roughly the same and the island width is strongly reduced thus indicating the superiority of this configuration. Plasma rotation (v t max = 180 km s −1 ) reduces the width W m=2,n=1 to a small value. (However, tearing mode physics which may lead to mode locking is not included in this consideration.

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Section: Conclusion and Discussionmentioning

confidence: 99%

Interaction of plasma rotation and resonant magnetic perturbation fields in tokamaks

Nicolai¹,

Daybelge²,

Lehnen³

et al. 2008

Nucl. Fusion

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“…The 100-keV (H) DNB has a mandate to deliver a 18-20 A of NB current and a 3-s 5-Hz pulse train every 20 s over ∼22-m transport length, necessitating a design of a beam production and transmission system, which betters the state of the art [1]. The system is housed in the NB cell and shares port #4 along in close proximity of the H&CD injector [2] beam lines in the NB cell. In principle, both positive as well as negative ion beams can be used to produce the desired neutrals.…”

Section: Introductionmentioning

confidence: 99%

Diagnostic Neutral Beam for ITER—Concept to Engineering

Chakraborty

Rotti

Bandyopadhyay

et al. 2010

IEEE Trans. Plasma Sci.

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Following the allocation of the procurement of the diagnostic neutral beam (DNB) to the Indian DA, a series of tasks have been undertaken to first assess the DNB configuration and arrive at an optimal beam-line configuration folding in the gas-feed and vacuum-pumping requirements. Specific emphasis is placed on the thermal, structural, and electrical designs of beam-line components, in order to ensure their compatibility with the criteria specified for ITER in vessel components, i.e., Structural Design Criteria for In-Vessel Components. The detailed assessment of manufacturing technologies and their compatibility with the ITER standards forms an integral part of the design. A common approach to manufacturing for DNB and heating-and-current-drive NB components shall be undertaken through a comprehensive prototyping phase which shall lead to built-to-print specifications. In addition to safety and remote-handling issues, the design also addresses the requirements of interfaces related to other systems such as cryo, hydraulic, pneumatic, vacuum pumping, gas feed, civil, power supplies and transmission, CODAC, etc. The successful delivery of DNB is dependent on two critical R&D aspects: 1) the production of a uniform low-divergence beam from the beam source and 2) a well-controlled transmission through lengths of ∼22 m. The first shall primarily be a subject of the Ion Source Test Facility-SPIDER [part of NB test facility (MITICA in Padova)]-where India is involved as a collaborator and the Indian test bed, where issues for DNB beam source which were not resolved in the SPIDER would be taken up. The second shall form one of the primary objectives of the Indian test bed to characterize the DNB. This paper presents the progress in DNB from the concept level to an engineered system along with the plans for system integration and an R&D intensive implementation.Index Terms-Beam transmission, beam-line components (BLCs), concept, diagnostic neutral beam (NB) (DNB), ITER.

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“…In the first design of the ITER neutral beam (NB) injector [1], a 1 MeV acceleration was chosen as a reasonable compromise between the heating, the current drive and the plasma rotation requirements and accordingly with the technological feasibility of the electrical insulations [2].…”

Section: Introductionmentioning

confidence: 99%

Adaptation of the 1 MV bushing to the SINGAP concept for the ITER NB injector test bed

Masiello¹

2006

Nucl. Fusion

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The 1 MV bushing of the ITER NB injector is probably one of the most challenging components of the whole accelerator, since such a high voltage (HV) in a contaminated and radiated environment requires the development of non-standard technologies. This paper intends to provide a guideline for the design of 1 MV bushing for the ITER neutral beam injector test bed. Although mainly focused on the SINGAP alternative concept of the injector, the reported general criteria can be useful for the design of other HV components, such as post insulators of the acceleration grids. For every different kind of required insulation, basic physical models describing breakdown phenomena are reported together with the main technological implications and the practical recommendations necessary to improve insulation performance. The results of the finite element analyses of 1 MV bushing, operating at CEA-Cadarache laboratories, are used to validate general criteria in a typical geometry. The effects of radiation, such as neutrons and gamma rays, on solid insulators and gases have also been taken into account, describing the most important phenomena and the related implications in terms of voltage hold-off capabilities. Finally the design of the bushing in the SINGAP option and the solutions adopted are described.

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ITER neutral beam system

Cited by 28 publications

References 3 publications

Interaction of plasma rotation and resonant magnetic perturbation fields in tokamaks

Interaction of plasma rotation and resonant magnetic perturbation fields in tokamaks

Diagnostic Neutral Beam for ITER—Concept to Engineering

Adaptation of the 1 MV bushing to the SINGAP concept for the ITER NB injector test bed

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