title: Electric field induced Lyman-α emission of a hydrogen beam for electric field measurements.
abstract: 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.
authors.affiliation: Aix-Marseille Université, CNRS, PIIM UMR 7345, FR-13397 Marseille Cedex 20, France.
authors.forename: L
authors.initials: L
authors.lastname: Chérigier-Kovacic
authors.affiliation: Department of Fusion Plasma Physics, Royal Institute of Technology (KTH), Teknikringen 31, 100 44 Stockholm, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Ström
authors.affiliation: CAMECA SAS - 29 Quai des Grésillons, 92622 Gennevilliers Cedex, France.
authors.forename: A
authors.initials: A
authors.lastname: Lejeune
authors.affiliation: Aix-Marseille Université, CNRS, PIIM UMR 7345, FR-13397 Marseille Cedex 20, France.
authors.forename: F
authors.initials: F
authors.lastname: Doveil