DBS

Contacts: Quinn Pratt, Stephen Storment

Short Description

Multi-channel Doppler back-scattering (DBS) diagnostic analysis

Keywords

DBS, Flow Velocity, Turbulence, Density Fluctuations

Long Description

The OMFIT - DBS module provides an integrated approach to analyzing data from the UCLA multi-channel Doppler back-scattering (DBS) diagnostics installed on the DIII-D and MAST(U) tokamaks. Data from both DIII-D V-band systems (one at the 60-deg port, another at the 240-port) along with legacy systems (e.g. W-band, ‘DBS5’) are available for analysis. On MAST(U) we support data from both V-band and Q-band systems. Analysis is generally performed over multiple times slices (usually order ~ 10) which are 20-200 ms (typical) in length. Labor-intensive frequency-domain analysis (fitting Doppler-shifted spectral components) is possible with the DBS_SPECTROGRAM_GUI. Ray tracing (using GENRAY) is used to calculate scattering parameters. We also support 3D beam-tracing with the SCOTTY and TORBEAM codes. DBS outputs include: probed radial locations, probed wavenumbers wavenumbers, flow velocity of turbulent structures, radial electric field, omega_E.

Typical workflows

• Fetch raw DBS data

• (Optional) ELM filtering

• DBS spectrum analysis and visualization

  • Doppler shift calculation

  • Spectral power calculation

• GENRAY/SCOTTY/TORBEAM setup with EFIT geqdsk and profiles (OMFITprofile, pFiles, input.gacode, etc…)

• Run Ray/Beam tracing with DBS launch parameters

• Calculate derived quantities and plot

• Plan for experiments (ray tracing angle-scans)

Supported devices

• DIII-D

• MAST

• NSTX

Tutorials

• Google docs tutorial

Relevant publications

• Peebles, W. A., et al. “A novel, multichannel, comb-frequency Doppler backscatter system.” Review of Scientific Instruments 81.10 (2010): 10D902.

• Rhodes, T. L., et al. “Optimized quasi-optical cross-polarization scattering system for the measurement of magnetic turbulence on the DIII-D tokamak.” Review of Scientific Instruments 89.10 (2018): 10H107.

Classes

• omfit_classes.omfit_base.OMFITcollection()

• omfit_classes.omfit_csv.OMFITcsv()

• omfit_classes.omfit_elm.OMFITelm()

• omfit_classes.omfit_eqdsk.OMFITgeqdsk()

• omfit_classes.omfit_genray.OMFITgenray()

• omfit_classes.omfit_google_sheet.OMFITgoogleSheet()

• omfit_classes.omfit_mds.OMFITmdsValue()

• omfit_classes.omfit_mds.OMFITmds()

• omfit_classes.omfit_profiles.OMFITprofiles()

• omfit_classes.omfit_thomson.OMFITthomson()

Contributors

List of contributors sorted by number of lines authored:

24763 Quinn Pratt
  658 Stephen Storment
  123 Clive Michael
   13 Will DeShazer
   11 Orso Meneghini
    2 Bhavin Patel
    1 Fusion Bot

Submodules

• GENRAY

Users

List of usernames sorted by number of module imports: ashourvana, prattq, ernst, smithsp, hongrongjie, yuguanying, houshman, kobayashi, fernandezp, grierson, krietedm, meneghini, schmitzl