Electric field induced Lyman-alpha emission of a hydrogen beam for electric field measurements
2015 (English)In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 86, no 6, 063504Article in journal (Refereed) Published
Electric field induced Lyman-alpha emission is a new way of measuring weak electric fields in vacuum and in a plasma. It is based on the emission of Lyman-alpha 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.
Place, publisher, year, edition, pages
2015. Vol. 86, no 6, 063504
Fusion, Plasma and Space Physics
IdentifiersURN: urn:nbn:se:kth:diva-172502DOI: 10.1063/1.4922856ISI: 000357690300015PubMedID: 26133836ScopusID: 2-s2.0-84933575644OAI: oai:DiVA.org:kth-172502DiVA: diva2:848544
QC 201508252015-08-252015-08-252015-08-25Bibliographically approved