Tokamak turbulence simulations using BOUT$++$ framework in core region

Development of a self-consistent, core-edge integrated simulation capability is a long standing problem in fusion simulation program. Such capability would yield insight into questions related to global profile dynamics originating from L to H and internal transport barrier (ITB) transitions. Starting from a tokamak edge plasma simulation code, BOUT$++$ has evolved into a versatile framework that can be used to simulate a wide range of fluid models in complicated magnetic geometry. For the realization of the self-consistent core-edge coupled simulation, we developed a core gyro-Landau-fluid code using BOUT$++$ framework. The primary physics goal of this development is to realize ITB formation in the presence of non-resonant modes and to study effects of flat q-profile and rotation shear on core profile de-stiffening. Initial efforts focused on the self-consistent simulation of core ITG turbulence and code verification. Verification of the code was realized by comparing linear growth rates calculated from BOUT$++$ with those from gyrokinetic codes. Global nonlinear simulations using 3$+$1 fields model were performed for ITG turbulence. Details of the code development and preliminary physics results will be presented.