Global Plasma Turbulence Simulations of $q=3$ Sawtoothlike Events in the RTP Tokamak

A two-fluid computer model of electromagnetic tokamak turbulence, CUTIE, is used to study the dynamic structure and turbulent transport in the Rijnhuizen Tokamak Project tokamak. A discharge with dominant, off-axis electron cyclotron heating is the main focus of the simulations which were extended over several resistive diffusion times. CUTIE reproduces the turbulent transport and MHD phenomena of the experiment. The noninductive components of the current density profile, viz., the dynamo current and the bootstrap current, are identified as key players in the turbulent transport and its suppression and in off-axis MHD events.

Figure 1

(a) Simulated $T_e$, and (b) $q$ waveforms.

Figure 2

Initial and time-averaged profiles: (a) $T_{e,i}$; (b) $n_e,q$.

Figure 3

Time-averaged (a) $P_{\mathrm{e}\mathrm{c}\mathrm{h}}$, $P_{\mathrm{o}\mathrm{h}\mathrm{m}}$, $P_{ei}$, and (b) advective electron heat flux.

Figure 4

Time-averaged (a) zonal flow, and (b) $j_{\mathrm{t}\mathrm{o}\mathrm{t}}$, $j_{\mathrm{d}\mathrm{y}\mathrm{n}}$, $j_{\mathrm{b}\mathrm{s}}$.

Figure 5

Waveforms of (a) $⟨(\delta v_r/v_d{)}^2⟩$, and (b) $⟨(\delta B_r/B_{\mathrm{p}\mathrm{o}\mathrm{l}}{)}^2⟩$.

Figure 6

(a) Simulated $T_e$ profiles at crash, and (b) experimental $T_e$ profiles at crash.