A phase contrast imaging–interferometer system for detection of multiscale electron density fluctuations on DIII-D

Journal Article · Mon Aug 15 00:00:00 EDT 2016 · Review of Scientific Instruments

DOI:https://doi.org/10.1063/1.4960727· OSTI ID:1371887

Davis, E. M.  ^[1]; Rost, J. C.  ^[1]; Porkolab, M. ^[1]; Marinoni, A. ^[1]; Van Zeeland, M. A. ^[2]

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1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center
2. General Atomics, San Diego, CA (United States)

Heterodyne interferometry and phase contrast imaging (PCI) are robust, mature techniques for measuring low-k and high-k electron density fluctuations, respectively. Here, we describe the first-ever implementation of a combined PCI-interferometer. The combined system uses a single 10:6 μm probe beam, two interference schemes, and two detectors to measure electron density uctuations at large spatiotemporal bandwidth (10 kHz < f < 5MHz and 0 cm^-1 ≤ k ≤ 20 cm^-1), allowing simultaneous measurement of ion- and electron-scale instabilities. Further, correlating our interferometer's measurements with those from DIII-D's pre-existing, toroidally separated interferometer allows core-localized, low-n MHD studies that may otherwise be inaccessible via external magnetic measurements. In the combined diagnostic's small port requirements and minimal access restrictions make it well-suited to the harsh neutron environments and limited port space expected in next-step devices.

• Research Organization: General Atomics, San Diego, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Fusion Energy Sciences (FES)
• Grant/Contract Number: FC02-04ER54698; FG02-94ER54235; FC02-99ER54512
• OSTI ID: 1371887
• Journal Information: Review of Scientific Instruments, Vol. 87, Issue 11; Related Information: E.M. Davis, J.C. Rost, M. Porkolab, A. Marinoni, and M.A. Van Zeeland, "A phase contrast imaging-interferometer system for detection of multiscale electron density fluctuations on DIII-D", Rev. Sci. Instr. 87, 11E117 (2016); ISSN 0034-6748
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY