Numerical simulation of ETG fluid model in uniformly sheared $E\times B$ velocity

We construct an ETG fluid model (Horton et al. Nucl. Fusion 45, 2005) with uniformly sheared $E\times B$ velocity. The fluid model is implemented based on the pseudospectral method. The linear dynamics calculation is performed in the moving frame, where the periodicity is assumed in the Lagrangian coordinate, and the nonlinear term is implemented in the traditional Fourier transformation (Lithwick, arXiv:astro-ph/0702046, 2007). This method enables us to investigate the nonlinear dynamics in sheared flow at a typical growth rate $\gamma > \omega_E$, for which we observed long-lived vortex structures when no instability is included (Kim et al. Phys. Plasma 13, 2304, 2006). We will report the spectrum for the electrostatic potential and the temperature.