Laser Heated Emissive Probes Design and Development under National Fusion Program and Potential Measurement

作     者：MEHTA Payal SARMA Arun GHOSH Joydeep 

作者机构：Venus International College of Technology Gandhinagar Gujarat India School of Advanced Sciences VIT University Chennai Vandalur-Kelambakkam Road Chennai 600127 India Institute for Plasma Research Bhat Gandhinagar 382428 Gujarat India 

基　　金：Supported by the Board of Research in Fusion Science and Technology of Government of India 

出 版 物：《Chinese Physics Letters》 (中国物理快报（英文版）)

年 卷 期：2014年第31卷第12期

页      码：74-78页

摘      要：Emissive probes are the tools for the direct deter- mination of the plasma potential ~PL and they deliver a more reliable measure of φPL compared to the indi- rect measurements with cold Langmuir probes. The emissive probe works on the principle of compensating the well-known asymmetry of the I-V characteristic of a single cold Langmuir probe by an electron emission current from the probe into the plasma. In an ideal case, the saturated value of floating potential V（А,em） of a highly emissive probe should equal the plasma potential. A conventional emissive probe usu- ally consists of a loop of tungsten wire heated by an electric current passing through it. These conven- tional emissive probes containing an electric current- heated metal wire loop suffer a huge drawback when it comes to their lifetime. The metal wire used in these probes evaporates and subsequently breaks when heated with high current, leading to frequent replacements of these wires. When used in ultra high vacuum （UHV） plasma systems, frequent replacement of these wires requires frequent vacuum breaks in the plasma systems. In many plasma systems espe- cially in magnetized toroidal hot plasmas like toka- maks, where determination of the electric fields leads to a great deal of useful information, frequent breaking of the vacuum is impossible for changing the filament of the emissive probes. Hence, along with the other drawbacks of the conventional emissive probes such as limited emission current, bending in a magnetic field makes their use impractical in these plasma systems. The most suitable alternative is the emissive probes heated by a focused infra-red laser. Due to them having several advantages over the conventional emis- sive probes, laser heated emissive probes （LHEPs） are found to have more and more uses in plasma systems. The advantages of the LHEP are： longer lifetime （no filament breaking issues）, attainment of higher tem- perature without melting or evaporation and thus higher emissivi

主 题 词：Laser heating Emissivity Plasma potentials Nuclear fusion Laser materials processing 

学科分类：07[理学] 081203[081203] 08[工学] 0805[工学-能源动力学] 070204[070204] 0835[0835] 0704[理学-天文学类] 0702[理学-物理学类] 0812[工学-测绘类] 

核心收录：

D　O　I：10.1088/0256-307X/31/12/125201

馆 藏 号：203689748...