Numerical simulation of the RF plasma discharge in the Linac4 H- ion source

S. Mattei, K. Nishida, M. Onai, J. Lettry, M. Q. Tran, Akiyoshi Hatayama

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Citations (Scopus)

Abstract

This paper presents a Particle-In-Cell Monte Carlo Collision simulation of the Radio-Frequency (RF) plasma heating in the Linac4 H- ion source at CERN. The model self-consistently takes into account the electromagnetic field generated by the RF coil, the external static magnetic fields and the resulting plasma response, including a kinetic description of the charged species (e-, H+, H2 +, H3 +, H-), as well as the atomic and molecular (vibrationally resolved) populations. The simulation is performed for the nominal operational condition of 40 kW RF power and 3 Pa H2 pressure. Results show that the plasma spatial distribution is non-uniform in the plasma chamber, with a density peak of ne = 5 • 1019 m-3 in the RF coil region. In the filter field region the electron density drops by two orders of magnitude, with a substantial reduction of the electron energy as well. This results in a ratio e/H-≈ 1 in the extraction region. The vibrational population is characterized by a two temperature distribution, with the high vibrational states showing a factor 2 higher termperature. A very good agreement is found between the simulation results and optical emission spectroscopy measurement performed on a dedicated test stand at CERN.

Original languageEnglish
Title of host publication5th International Symposium on Negative Ions, Beams and Sources, NIBS 2016
PublisherAmerican Institute of Physics Inc.
Volume1869
ISBN (Electronic)9780735415492
DOIs
Publication statusPublished - 2017 Aug 9
Event5th International Symposium on Negative Ions, Beams and Sources, NIBS 2016 - Oxford, United Kingdom
Duration: 2016 Sep 122016 Sep 16

Other

Other5th International Symposium on Negative Ions, Beams and Sources, NIBS 2016
CountryUnited Kingdom
CityOxford
Period16/9/1216/9/16

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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    Mattei, S., Nishida, K., Onai, M., Lettry, J., Tran, M. Q., & Hatayama, A. (2017). Numerical simulation of the RF plasma discharge in the Linac4 H- ion source. In 5th International Symposium on Negative Ions, Beams and Sources, NIBS 2016 (Vol. 1869). [030018] American Institute of Physics Inc.. https://doi.org/10.1063/1.4995738