Numerical computation of the transport matrix in a tokamak plasma with electrostatic turbulence

Based on the phase-space nonlinear turbulent transport equation, a numerical code NDTM (Numerical Diagnosis of Transport Matrix) is developed to compute the transport matrix in a tokamak plasma with nonlinear electrostatic turbulence. The NDTM code can be used as a diagnostic tool for a nonlinear gyrokinetic turbulence simulation code, it obtains the transport matrix from the gyrocenter orbits in the fluctuating field found by the latter. As an application, we use the code to compute the ion transport matrix in a nonlinear ion-temperature-gradient-driven turbulence field found by the NLT code. The computed transport matrix indicates an inward thermal pinch driven by the density gradient and an inward particle pinch driven by the temperature gradient. The ion effective heat diffusivity and effective particle diffusivity are computed by the transport matrix; the numerical results agree well with NLT results.