Two-dimensional phase contrast interferometer for fluctuations study on LHD

• DOI: 10.1063/1.1784528
• Publication Date: 2004-10-04T22:09:44Z
• Authors: A. L. Sanin; K. Tanaka; L. N. Vyacheslavov; K. Kawahata; T. Akiyama
• Keywords: 0103 physical sciences; 01 natural sciences

C O 2 laser based phase contrast interferometer was used previously on LHD to study plasma density microfluctuations. New two-dimensional 6×8 elements array of CdHgTe photoconductors was employed for detection. In addition to commonly measured intensity, frequency spectrum, and two-point correlation two-dimensional detector array allows determining the direction of propagation of waves in plasma. From the angular distribution it is possible to obtain localized along the viewing line properties of fluctuations using strong magnetic shear in LHD. As a result, the radial profiles of density microfluctuations can be obtained with 1 μs temporal resolution determined by detector bandwidth. The described scheme was tested using ultrasonic wave in air. New imaging diagnostics has been installed on LHD and first experimental results are reported.