Transport modeling applying data assimilation techniques. Practical cases in LHD

In order to realize a system that can predict and control the behavior of fusion plasma, at high speed and with a high degree of accuracy, the authors are constructing a data assimilation system based on the integrated transport simulation code. Data assimilation is a technology that combines simulation and observation to optimize the simulation model through observation. Data assimilation is also expected to play an important role in the field of nuclear fusion. This paper introduces the concept of data assimilation and the practical examples of large helical devices (LHD), and describes the related issues and future prospects of the current data assimilation system. (A.O.)