Abstract
A novel multichannel, tunable Doppler backscattering (DBS)/reflectometry system has recently been developed and applied to a variety of DIII-D plasmas. Either DBS or reflectometry can be easily configured for use in a wide range of plasma conditions using a flexible quasi-optical antenna system. The multiple closely spaced channels, when combined with other fluctuation diagnostic systems, have opened up new measurements of plasma properties. For example, the toroidal and fine-scale radial structure of coherent plasma oscillations, such as geodesic acoustic modes, have been probed simultaneously in the core of high temperature plasmas by applying correlation analysis between two toroidally separated DBS systems, as well as within the multichannel array. When configured as a reflectometer, cross-correlation with electron cyclotron emission radiometry has uncovered detailed information regarding the crossphase relationship between density and temperature fluctuations. The density-temperature crossphase measurement yields insight into the physics of tokamak turbulence at a fundamental level that can be directly compared with predictions from nonlinear gyrokinetic simulations.
| Original language | English |
|---|---|
| Article number | 10D907 |
| Journal | Review of Scientific Instruments |
| Volume | 81 |
| Issue number | 10 |
| DOIs | |
| State | Published - Oct 2010 |
| Externally published | Yes |
Funding
This research was supported by U.S. Department of Energy under Grant Nos. DE-FG02-08ER54984 and DE-FG03-01ER54615 and Contract No. DE-FC02-04ER54698. J.C.H.’s work was performed through the Fusion Energy Sciences Fellowship Program administered by Oak Ridge Institute for Science and Education under a contract between the U.S. Department of Energy and the Oak Ridge Associated Universities. The authors would like to thank the entire team at DIII-D for their support of these experiments. The authors would also like to thank C. Wannberg, X. Nguyen, and R. Martin for their technical support.