Benchmarking of the NBI block in ASTRA code versus the OFMC calculations

The description of the Neutral Beam Injection block in the 1.5D ASTRA code is presented including the neutral beam absorption, first orbit analysis and fast ion slowing down. Benchmarking in the ASTRA code is carried out using the OFMC calculations for the JT60-U experimental parameters. The benchmarking reveals that the NBI solver of the ASTRA code provides satisfactory accuracy of the absorbed power and generated current calculations. Taking account of ripple losses and the multistep atomic processes for the high energy NBI enables calculation of both the transversal NBI in the rippled field and the tangential negative beam injection in the JT60-U experiments. The fast and self-consistent treatment of all plasma parameters in a MHD equilibrium makes the ASTRA code extremely convenient for the experimental data analysis and plasma transport simulations in the JT60-U experiments. (author)