Experimental Investigation of Dynamical Coupling between Turbulent Transport and Parallel Flows in the JET Plasma-Boundary Region

The dynamical coupling between turbulent transport and parallel flows has been investigated in the plasma boundary region of the Joint European Torus tokamak. Experimental results show that there is a dynamical relationship between transport and parallel flows. As the size of transport events increases, parallel flows also increase. These results show that turbulent transport can drive parallel flows in the plasma boundary of fusion plasmas. This new type of measurement is an important element to unravel the overall picture connecting radial transport and flows in fusion plasmas.

Figure 1

Time evolution of $E\times B$ turbulent transport and parallel flows in the JET scrape-off-layer region ($r-r_{\mathrm{L}\mathrm{C}\mathrm{F}\mathrm{S}}\approx 2\mathrm{c}\mathrm{m}$, midplane).

Figure 2

Expected number of the parallel Mach number versus local turbulent transport ($r-r_{\mathrm{L}\mathrm{C}\mathrm{F}\mathrm{S}}\approx 0.5–2\mathrm{c}\mathrm{m}$, midplane).

Figure 3

PDFs of parallel Mach numbers versus turbulent transport computed at different time scales ($2–80\mu \mathrm{s}$). Measurements were taken at $r-r_{\mathrm{L}\mathrm{C}\mathrm{F}\mathrm{S}}\approx 0.5\mathrm{c}\mathrm{m}$ (shot 56846) and $r-r_{\mathrm{L}\mathrm{C}\mathrm{F}\mathrm{S}}\approx 2\mathrm{c}\mathrm{m}$ (shot 56845).