Section 58
Chapter 57,746

Electric field induced Lyman-α emission of a hydrogen beam for electric field measurements

Chérigier-Kovacic, L.; Ström, P.; Lejeune, A.; Doveil, F.

Review of Scientific Instruments 86(6): 063504


ISSN/ISBN: 1089-7623
PMID: 26133836
DOI: 10.1063/1.4922856
Accession: 057745912

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Electric field induced Lyman-α emission is a new way of measuring weak electric fields in vacuum and in a plasma. It is based on the emission of Lyman-α radiation (121.6 nm) by a low-energy metastable H atom beam due to Stark-quenching of the 2s level induced by the field. In this paper, we describe the technique in detail. Test measurements have been performed in vacuum between two plates polarized at a controlled voltage. The intensity of emitted radiation, proportional to the square of the field modulus, has been recorded by a lock-in technique, which gives an excellent signal to noise ratio. These measurements provide an in situ calibration that can be used to obtain the absolute value of the electric field. A diagnostic of this type can help to address a long standing challenge in plasma physics, namely, the problem of measuring electric fields without disturbing the equilibrium of the system that is being studied.

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