Voltage holding optimization of the MITICA electrostatic accelerator

N. Pilan, P. Bettini, A. De Lorenzi, R. Specogna

Research output: Contribution to journalArticle

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Two Heating Neutral Beam Injectors (H-NBI) are planned to be installed in ITER with a total delivered heating power of 33 MW [1]. The main parameters are: 870 kV acceleration voltage with 46 A beam current for hydrogen beam, and 1 MV voltage with 40 A current for deuterium beam. The voltage holding in the 1 MV ITER Neutral Beam Accelerator is recognized to be one of the most critical issues for long pulse (3600 s) beam operation, due to the complex electrostatic structure formed by electrodes polarized at different potentials immersed in vacuum or low-pressure gas. As a matter of fact, the system shall work in a p × d range at the left of the Paschen curve where the classical Townsend breakdown criterion is no longer valid. The voltage holding is governed by the mechanism of the long gap insulation in high vacuum, not yet well consolidated from the physical point of view. This paper is aimed to describe the optimization of the voltage holding capability for MITICA electrostatic accelerator. The results of this analysis will constitute the input for the probabilistic model [3] which is adopted to predict the breakdown probability by means of 2D analyses of the multi electrode - multi voltage system. © 2013 Consorzio RFX Associazione Euratom ENEA sulla Fusione.
Original languageEnglish
Pages (from-to)1038 - 1041
Number of pages4
JournalFusion Engineering and Design
Issue number6-8
Publication statusPublished - 2013
Externally publishedYes


All Science Journal Classification (ASJC) codes

  • Civil and Structural Engineering
  • Nuclear Energy and Engineering
  • Materials Science(all)
  • Mechanical Engineering

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