Lamb-shift and electric field measurements in plasmas
2017 (English)In: Plasma Physics and Controlled Fusion, ISSN 0741-3335, E-ISSN 1361-6587, Vol. 59, no 1, 014020Article in journal (Refereed) Published
The electric field is a quantity of particular relevance in plasma physics. Indeed, its fluctuations are responsible for different macroscopic phenomena such as anomalous transport in fusion plasmas. Answering a long-standing challenge, we offer a new method to locally and non-intrusively measure weak electric fields and their fluctuations in plasmas, by means of a beam of hydrogen ions or atoms. We present measurements of the electric field in vacuum and in a plasma where Debye shielding is measured. For the first time, we have used the Lamb-shift resonance to measure oscillating electric fields around 1 GHz and observed the strong enhancement of the Lyman-alpha signal. The measurement is both direct and non-intrusive. This method provides sensitivity (mV cm(-1)) and temporal resolution (ns) that are three orders higher compared to current diagnostics. It thus allows measuring fluctuations of the electric field at scales not previously reached experimentally.
Place, publisher, year, edition, pages
Institute of Physics Publishing , 2017. Vol. 59, no 1, 014020
basic plasma physics, Debye shielding, plasma sheath, Lamb shift, Stark mixing
IdentifiersURN: urn:nbn:se:kth:diva-196965DOI: 10.1088/0741-3335/59/1/014020ISI: 000386799100003ScopusID: 2-s2.0-85006021619OAI: oai:DiVA.org:kth-196965DiVA: diva2:1056017
QC 201612132016-12-132016-11-282017-01-10Bibliographically approved