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Fast soft x-ray images of magnetohydrodynamic phenomena in NSTX...

Publication Type
Conference Paper
Journal Name
Review of Scientific Instruments
Publication Date
Page Number
10E928
Volume
79
Issue
10
Conference Name
17th Topical Conference on High-Temperature Plasma Diagnostics
Conference Location
Albuquerque, New Mexico, United States of America
Conference Date
-

A variety of magnetohydrodynamic (MHD) phenomena have been observed on NSTX. Many of these affect fast particle losses, which are of major concern for future burning plasma experiments. Usual diagnostics for studying these phenomena are arrays of Mirnov coils for magnetic oscillations and p-i-n diode arrays for soft x-ray emission from the plasma core. Data reported here are from a unique fast soft x-ray imaging camera (FSXIC) with a wide-angle (pinhole) tangential view of the entire plasma minor cross section. The camera provides a 64x64 pixel image, on a charge coupled device chip, of light resulting from conversion of soft x rays incident on a phosphor to the visible. We have acquired plasma images at frame rates of 1-500 kHz (300 frames/shot) and have observed a variety of MHD phenomena: disruptions, sawteeth, fishbones, tearing modes, and edge localized modes (ELMs). New data including modes with frequency >90 kHz are also presented. Data analysis and modeling techniques used to interpret the FSXIC data are described and compared, and FSXIC results are compared to Mirnov and p-i-n diode array results.