Estimation of the Lyman-α signal of the EFILE diagnostic under static or radiofrequency electric field in vacuum

作     者：Carlo POGGI Theo GUILLAUME Fabrice DOVEIL Laurence CHIERIGIER-KOVACIC carlo poggi;théo guillaume;fabrice doveil;laurence chérigier-kovacic

作者机构：Consorzio RFXCorso Stati UnitiI-35127 PadovaItaly Aix-Marseille UniversiteCNRSPIIM UMR 7345F-13397 Marseille Cedex 20France 

出 版 物：《Plasma Science and Technology》 (等离子体科学和技术（英文版）)

年 卷 期：2018年第20卷第7期

页      面：1-6页

核心收录：

学科分类：080801[工学-电机与电器] 0808[工学-电气工程] 082903[工学-林产化学加工工程] 08[工学] 0829[工学-林业工程] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 082201[工学-制浆造纸工程] 0822[工学-轻工技术与工程] 

基　　金：from an Erasmus exchange grant via the European Erasmus+ Programme 2014-2020 

主　　题：electric field measurement electromagnetic simulations Stark effect plasma diagnostics 

摘      要：The electric field induced Lyman-a emission diagnostic aims to provide a non intrusive and precise measurement of the electric field in plasma, using a beam of hydrogen atoms prepared in the metastable 2s state. The metastable particles are obtained by means of a proton beam extracted from a hydrogen plasma source, and neutralised by interaction with vaporised caesium. When a 2s atom enters a region where an electric field is present, it undergoes a transition to the 2p state （Stark mixing）. It then quickly decays to the ground level, emitting Lyman-a radiation, which is collected by a photomultiplier. The 2s → 2p transition rate is proportional to the square of the magnitude of the electric field, and depends on the field oscillation frequency （with peaks around l GHz）. By measuring the intensity of the Lyman-a radiation emitted by the beam it is possible to determine the magnitude of the field in a defined region. In this work, an analysis of the behaviour of the diagnostic under static or radiofrequency electric field is presented. Electric field simulations obtained with a finite element solver of Maxwell equations, combined with theoretical calculations of the Stark mixing transition rate, are used to develop a model for the interpretation of photomultiplier data. This method shows good agreement with experimental results for the static field case, and allows to measure the field magnitude for the oscillating case.