Issue date: 2019
Rights:
Creative Commons Attribution 4.0 International (CC BY)
Cite as:
Zweben, S. J., Myra, J. R., Diallo, A., Russell, D. A., Scotti, F., & Stotler, D. P. (2019). Blob wakes in NSTX [Data set]. Princeton Plasma Physics Laboratory, Princeton University. https://doi.org/10.11578/1562095
@electronic{zweben_s_j_2019,
  author      = {Zweben, S. J. and
                Myra, J. R. and
                Diallo, A. and
                Russell, D. A. and
                Scotti, F. and
                Stotler, D. P.},
  title       = {{Blob wakes in NSTX}},
  publisher   = {{Princeton Plasma Physics Laboratory, Pri
                nceton University}},
  year        = 2019,
  url         = {https://doi.org/10.11578/1562095}
}
Description:

Transient small-scale structures were identified in the wake of blobs moving poloidally through the SOL of high-powered H-mode plasmas in NSTX, using the gas puff imaging (GPI) diagnostic. These blob wakes had a poloidal wavelength in the range 3.5 cm, which is significantly smaller than the average blob scale of~12 cm, and the wakes had a poloidal velocity of 1.5 km/sec in the electron diamagnetic direction, which is opposite to the blob poloidal velocity in these shots. These wakes were radially localized 0-4 cm outside the separatrix and occurred within ~50 microsec after the passage of a blob through the GPI field of view. The clearest wakes were seen when the GPI viewing angle was well aligned with the local B field line, as expected for such small-scale structures given the diagnostic geometry. A plausible theoretical interpretation of the wakes is discussed: the observed wakes share some features of drift waves and/or drift-Alfven waves which could be excited by the blobs.

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