MITICA (Megavolt ITER Injector Concept Advancement) is a test facility planned to be built at Consorzio RFX for the development of the full-size Heating and Current Drive Neutral Beam Injectors for the ITER Tokamak reactor [1]. The core of MITICA [2] is constituted by a RF-driven negative Ion Source and by a multi-grid electrostatic accelerator, which shall produce a 46A H- ion Beam (or a 40A D- ion Beam) with a specific energy up to 1 MeV. The beam is formed by 1280 individual beamlets (4x4 groups of 16x5 circular apertures) with an overall cross-section of ~ 600 x 1600 mm2. The beamlets are to be extracted, accelerated and neutralized under well-controlled conditions in order to obtain a focused 1 MeV, 17 MW Neutral Beam on a 400 x 560 mm2 target at ~25 m. The electrostatic and magnetic configuration inside the beam source and the accelerator [3] are of crucial importance for the achievement of the required beam optics quality (with correction of undesired deflections) and also of a good beam efficiency (with early deflection of co-extracted and stripped electrons). Several alternative magnetic design concepts have been considered. The most promising design concepts have been compared from the physics and engineering point of view, in terms of: - beam optics (beamlet divergence, beam aiming) - electron suppression capability (co-extracted and generated by stripping reactions) - thermo-mechanical loads on accelerator grids (stress, strain, deformation, fatigue life). The paper presents the rationale of the various steps of this process and the final results obtained. This work was set up with partial financial support of Fusion for Energy (F4E), the European Union's Joint Undertaking for ITER. The views and opinions expressed herein do not necessarily reflect those of F4E, nor those of the ITER Organization. [1] R. Hemsworth, H. Decamps, J. Graceffa et al., Nucl. Fusion 49 (2009) 045006. [2] P. Sonato, P. Agostinetti, G. Anaclerio, et al. Fusion Eng. and Design, Vol. 84, 269-274 (2009). [3] G. Chitarin; P. Agostinetti; N. Marconato; D. Marcuzzi; E. Sartori; G. Serianni; P. Sonato Rev. of Sci Instr., vol. 83, 2B107-1 (2012)
Optimization of the electrostatic and magnetic field configuration in the MITICA accelerator
Piero Agostinetti;Gianluigi Serianni;
2012
Abstract
MITICA (Megavolt ITER Injector Concept Advancement) is a test facility planned to be built at Consorzio RFX for the development of the full-size Heating and Current Drive Neutral Beam Injectors for the ITER Tokamak reactor [1]. The core of MITICA [2] is constituted by a RF-driven negative Ion Source and by a multi-grid electrostatic accelerator, which shall produce a 46A H- ion Beam (or a 40A D- ion Beam) with a specific energy up to 1 MeV. The beam is formed by 1280 individual beamlets (4x4 groups of 16x5 circular apertures) with an overall cross-section of ~ 600 x 1600 mm2. The beamlets are to be extracted, accelerated and neutralized under well-controlled conditions in order to obtain a focused 1 MeV, 17 MW Neutral Beam on a 400 x 560 mm2 target at ~25 m. The electrostatic and magnetic configuration inside the beam source and the accelerator [3] are of crucial importance for the achievement of the required beam optics quality (with correction of undesired deflections) and also of a good beam efficiency (with early deflection of co-extracted and stripped electrons). Several alternative magnetic design concepts have been considered. The most promising design concepts have been compared from the physics and engineering point of view, in terms of: - beam optics (beamlet divergence, beam aiming) - electron suppression capability (co-extracted and generated by stripping reactions) - thermo-mechanical loads on accelerator grids (stress, strain, deformation, fatigue life). The paper presents the rationale of the various steps of this process and the final results obtained. This work was set up with partial financial support of Fusion for Energy (F4E), the European Union's Joint Undertaking for ITER. The views and opinions expressed herein do not necessarily reflect those of F4E, nor those of the ITER Organization. [1] R. Hemsworth, H. Decamps, J. Graceffa et al., Nucl. Fusion 49 (2009) 045006. [2] P. Sonato, P. Agostinetti, G. Anaclerio, et al. Fusion Eng. and Design, Vol. 84, 269-274 (2009). [3] G. Chitarin; P. Agostinetti; N. Marconato; D. Marcuzzi; E. Sartori; G. Serianni; P. Sonato Rev. of Sci Instr., vol. 83, 2B107-1 (2012)I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
