Blob wakes in NSTX

Zweben SJ, Myra JR, Diallo A, Russell DA, Scotti F, Stotler DP
Issue date: July 2019
Cite as:
Zweben SJ, Myra JR, Diallo A, Russell DA, Scotti F, Stotler DP. (2019). Blob wakes in NSTX [Data set]. Princeton Plasma Physics Laboratory, Princeton University.
@electronic{zweben_sj_myra_jr_diallo_a_russell_da_scotti_f_stotler_dp_2019,
  author      = {Zweben SJ, Myra JR, Diallo A, Russell DA, Scotti F, Stotler DP},
  title       = {{Blob wakes in NSTX}},
  publisher   = {{Princeton Plasma Physics Laboratory, Pri
                nceton University}},
  year        = 2019
}
Abstract:

Transient small-scale structures were identified in the wake of blobs movingpoloidally through the SOL of high-powered H-mode plasmas in NSTX, using the gaspuff imaging (GPI) diagnostic. These blob wakes had a poloidal wavelength in therange 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 theelectron diamagnetic direction, which is opposite to the blob poloidal velocity inthese shots. These wakes were radially localized 0-4 cm outside the separatrix andoccurred 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 thelocal B field line, as expected for such small-scale structures given the diagnosticgeometry. A plausible theoretical interpretation of the wakes is discussed: theobserved wakes share some features of drift waves and/or drift-Alfven waves whichcould be excited

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