On the meniscus formation and the negative hydrogen ion extraction from ITER neutral beam injection relevant ion source

被引:23
作者
Mochalskyy, S. [1 ]
Wuenderlich, D. [1 ]
Ruf, B. [1 ]
Fantz, U. [1 ]
Franzen, P. [1 ]
Minea, T. [2 ]
机构
[1] Max Planck Inst Plasma Phys, EURATOM Assoc, D-85748 Garching, Germany
[2] Univ Paris 11, CNRS, Phys Gaz & Plasmas Lab, F-91405 Orsay, France
关键词
ITER NBI; PIC plasma modelling; plasma source; negative ion extraction; ACCELERATOR; DESIGN; PLASMA;
D O I
10.1088/0741-3335/56/10/105001
中图分类号
O35 [流体力学]; O53 [等离子体物理学];
学科分类号
070204 ; 080103 ; 080704 ;
摘要
The development of a large area (A(source,ITER) = 0.9 x 2 m(2)) hydrogen negative ion (NI) source constitutes a crucial step in construction of the neutral beam injectors of the international fusion reactor ITER. To understand the plasma behaviour in the boundary layer close to the extraction system the 3D PIC MCC code ONIX is exploited. Direct cross checked analysis of the simulation and experimental results from the ITER-relevant BATMAN source testbed with a smaller area (A(source,BATMAN) approximate to 0.32 x 0.59 m(2)) has been conducted for a low perveance beam, but for a full set of plasma parameters available. ONIX has been partially benchmarked by comparison to the results obtained using the commercial particle tracing code for positive ion extraction KOBRA3D. Very good agreement has been found in terms of meniscus position and its shape for simulations of different plasma densities. The influence of the initial plasma composition on the final meniscus structure was then investigated for NIs. As expected from the Child-Langmuir law, the results show that not only does the extraction potential play a crucial role on the meniscus formation, but also the initial plasma density and its electronegativity. For the given parameters, the calculated meniscus locates a few mm downstream of the plasma grid aperture provoking a direct NI extraction. Most of the surface produced NIs do not reach the plasma bulk, but move directly towards the extraction grid guided by the extraction field. Even for artificially increased electronegativity of the bulk plasma the extracted NI current from this region is low. This observation indicates a high relevance of the direct NI extraction. These calculations show that the extracted NI current from the bulk region is low even if a complete ion-ion plasma is assumed, meaning that direct extraction from surface produced ions should be present in order to obtain sufficiently high extracted NI current density. The calculated extracted currents, both ions and electrons, agree rather well with the experiment.
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页数:11
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共 53 条
  • [1] Negative hydrogen ion production in fusion dedicated ion sources
    Bacal, M.
    [J]. CHEMICAL PHYSICS, 2012, 398 : 3 - 6
  • [2] POWERFUL INJECTOR OF NEUTRALS WITH A SURFACE-PLASMA SOURCE OF NEGATIVE-IONS
    BELCHENK.YI
    DIMOV, GI
    DUDNIKOV, VG
    [J]. NUCLEAR FUSION, 1974, 14 (01) : 113 - 114
  • [3] SURFACE NEGATIVE-ION PRODUCTION IN ION SOURCES
    BELCHENKO, Y
    [J]. REVIEW OF SCIENTIFIC INSTRUMENTS, 1993, 64 (06) : 1385 - 1393
  • [4] Cavity ring-down spectroscopy on a high power rf driven source for negative hydrogen ions
    Berger, M.
    Fantz, U.
    Christ-Koch, S.
    [J]. PLASMA SOURCES SCIENCE & TECHNOLOGY, 2009, 18 (02)
  • [5] Birdsall C K., 2018, Plasma Physics via Computer Simulation
  • [6] Physics of a magnetic filter for negative ion sources. II. E x B drift through the filter in a real geometry
    Boeuf, J. P.
    Claustre, J.
    Chaudhury, B.
    Fubiani, G.
    [J]. PHYSICS OF PLASMAS, 2012, 19 (11)
  • [7] Model of an inductively coupled negative ion source: II. Application to an ITER type source
    Boeuf, J. P.
    Hagelaar, G. J. M.
    Sarrailh, P.
    Fubiani, G.
    Kohen, N.
    [J]. PLASMA SOURCES SCIENCE & TECHNOLOGY, 2011, 20 (01)
  • [8] Partial differential equations of mathematical physics
    Courant, R
    Friedrichs, K
    Lewy, H
    [J]. MATHEMATISCHE ANNALEN, 1928, 100 : 32 - 74
  • [9] Status of Physics Design of the HNB Accelerator for ITER
    de Esch, H. P. L.
    Kashiwagi, M.
    Inoue, T.
    Serianni, G.
    Agostinetti, P.
    Chitarin, G.
    Marconato, N.
    Sartori, E.
    Sonato, P.
    Veltri, P.
    Hemsworth, R. S.
    [J]. THIRD INTERNATIONAL SYMPOSIUM ON NEGATIVE IONS, BEAMS AND SOURCES (NIBS 2012), 2013, 1515 : 512 - 521
  • [10] First results of the ITER-relevant negative ion beam test facility ELISE (invited)
    Fantz, U.
    Franzen, P.
    Heinemann, B.
    Wuenderlich, D.
    [J]. REVIEW OF SCIENTIFIC INSTRUMENTS, 2014, 85 (02)