Repository logo

Infoscience

  • English
  • French
Log In
Logo EPFL, École polytechnique fédérale de Lausanne

Infoscience

  • English
  • French
Log In
  1. Home
  2. Academic and Research Output
  3. Journal articles
  4. Negative ion characterization in a helicon plasma source for fusion neutral beams by cavity ring-down spectroscopy and Langmuir probe laser photodetachment
 
research article

Negative ion characterization in a helicon plasma source for fusion neutral beams by cavity ring-down spectroscopy and Langmuir probe laser photodetachment

Agnello, R.  
•
Bechu, S.
•
Furno, I  
Show more
February 1, 2020
Nuclear Fusion

Negative ions are characterized in the helicon plasma source resonant antenna ion device (RAID) at the Swiss plasma center by means of cavity ring-down spectroscopy (CRDS) and Langmuir probe (LP)-assisted laser photodetachment. A high density and axially homogeneous plasma column is produced via a RF antenna able to sustain the propagation of helicon waves in a steady state regime. An electron density n(e) congruent to 2.0 x 10(18) m(-3) in H-2 plasma at 0.3 Pa and 3 kW of input power is measured in the center of the plasma column by LP and microwave interferometry. The electron temperature profile is peaked on axis reaching T-e approximate to 5 eV and decreasing to 1.5 eV at r = 0.05 m. Thus, a hot core region forms where H2 molecules are rovibrationally excited (H-2(nu)), and a cold edge, where low energy electrons can attach to H-2(nu) and produce H- ions by dissociative attachment. In this work we use LP-assisted laser photodetachment and CRDS diagnostics to measure H- and D- radial density profiles and how they depend on source parameters. We show that negative ions are distributed on a shell of 0.06 m radius with a peak value of similar to 2.0 x 10(16) m(-3) in H-2 plasma. These results suggest that, although substantial technical development is needed, helicon plasmas could be considered as a possible candidate as sources of negative ions for future NBIs.

  • Details
  • Metrics
Type
research article
DOI
10.1088/1741-4326/ab5e64
Web of Science ID

WOS:000539088800007

Author(s)
Agnello, R.  
Bechu, S.
Furno, I  
Guittienne, Ph
Howling, A. A.  
Jacquier, R.  
Plyushchev, G.  
Barbisan, M.
Pasqualotto, R.
Morgal, I
Show more
Date Issued

2020-02-01

Publisher

IOP Publishing Ltd

Published in
Nuclear Fusion
Volume

60

Issue

2

Article Number

026007

Subjects

Physics, Fluids & Plasmas

•

Physics

•

nuclear fusion

•

neutral beams

•

cavity ring-down spectroscopy

•

langmuir probe photodetachment

•

hydrogen

•

excitation

•

dependence

Editorial or Peer reviewed

REVIEWED

Written at

EPFL

EPFL units
SPC  
Available on Infoscience
June 25, 2020
Use this identifier to reference this record
https://infoscience.epfl.ch/handle/20.500.14299/169615
Logo EPFL, École polytechnique fédérale de Lausanne
  • Contact
  • infoscience@epfl.ch

  • Follow us on Facebook
  • Follow us on Instagram
  • Follow us on LinkedIn
  • Follow us on X
  • Follow us on Youtube
AccessibilityLegal noticePrivacy policyCookie settingsEnd User AgreementGet helpFeedback

Infoscience is a service managed and provided by the Library and IT Services of EPFL. © EPFL, tous droits réservés