Electric Field Induced Lyman-α Emission of a hydrogen beam for electric field measurements

Laurence Chérigier-Kovacic (1) , Peter Ström (2) , Aurélien Lejeune (1) , F Doveil (1)

1 PIIM - Physique des interactions ioniques et moléculaires
2 KTH - KTH Royal Institute of Technology [Stockholm]

EFILE (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 (121.6nm) 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.

Domaines: Instrumentations et Détecteurs [physics.ins-det]; Physique des plasmas [physics.plasm-ph]

Laurence Chérigier-Kovacic, Peter Ström, Aurélien Lejeune, F Doveil. Electric Field Induced Lyman-α Emission of a hydrogen beam for electric field measurements. Review of Scientific Instruments, 2015, 86 (6), pp.063504. ⟨10.1063/1.4922856⟩. ⟨hal-01466150⟩