  This paper provides a comprehensive review of the TRANSP code, a
sophisticated tool for interpretive and predictive analysis of tokamak plasmas,
detailing its major capabilities and features. It describes the equations for
particle, power, and momentum balance analysis, as well as the poloidal field
diffusion equations. The paper outlines the spatial and time grids used in
TRANSP and details the equilibrium assumptions and solvers. Various models for
heating and current drive, including updates to the NUBEAM model, are
discussed. The handling of large-scale events such as sawtooth crashes and
pellet injections is examined, along with the predictive capabilities for
advancing plasma profiles. The integration of TRANSP with the ITER Integrated
Modeling and Analysis Suite (IMAS) is highlighted, demonstrating enhanced data
access and analysis capabilities. Additionally, the paper discusses best
practices and continuous integration techniques to enhance TRANSP's robustness.
The suite of TRANSP tools, designed for efficient data analysis and simulation,
further supports the optimization of tokamak operations and coupling with other
tokamak codes. Continuous development and support ensure that TRANSP remains a
major code for the analysis of experimental data for controlled thermonuclear
fusion, maintaining its critical role in supporting the optimization of tokamak
operations and advancing fusion research.
