A Data-Assimilation Based Method for Equilibrium Reconstruction of Magnetic Fusion Plasma and its Application to Reversed Field Pinch

Akio Sanpei,Yasuaki Kuroe,Sadao Masamune,Takayuki Okamoto

doi:10.1109/access.2021.3081146

Akio Sanpei, Yasuaki Kuroe + Show 2 more

Open Access

https://doi.org/10.1109/access.2021.3081146

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Abstract

Carbon-free energy sources are essential to avoid global warming, and nuclear fusion is expected to play a major role in achieving clean and sustainable energy. In the development of magnetic fusion, there exist a lot of issues related with plasma equilibrium to be studied extensively, typical representative of which is a problem of equilibrium reconstruction of plasma. In this paper we propose a new method of equilibrium reconstruction for fusion plasma based on the data assimilation. Aiming at dealing not only with axisymmetric toroidal plasmas but also with more general toroidal plasmas, we formulate the problems of equilibrium reconstruction in generalized forms and derive methods to solve them. We also propose a method for applying the equilibrium reconstruction method to the reversed field pinch (RFP), and it is applied to a real RFP experimental apparatus for its evaluation. It is shown through numerical experiments that the proposed equilibrium reconstruction method works well with reasonable accuracy. And it is also shown through real experiments applying the RFP apparatus that the equilibrium of RFP plasma is appropriately reconstructed.

Highlights

Development of carbon-free energy sources with a less load to the environment is one of the urgent issues in ensuring human society and maintaining the sustainability of development
The objective of this paper is to propose a new method for reconstructing the equilibrium state of magnetic fusion plasma and to propose a method for applying it to reversed field pinch (RFP)
We propose a method of reconstructing equilibrium of magnetic fusion plasma based on data assimilation

Summary

Introduction

Development of carbon-free energy sources with a less load to the environment is one of the urgent issues in ensuring human society and maintaining the sustainability of development. Nuclear fusion is one of the candidates for the solution, and development of fusion reactor has been in progress to realize electric energy production from virtually unlimited fuel sources [1], [2]. The initial operation for plasma production in ITER is scheduled in 2025. In order to realize fusion plasma, the plasma has to be maintained in an equilibrium state where electromagnetic force acting on a plasma element balances with pressure force. The objective of this paper is to propose a new method for reconstructing the equilibrium state of magnetic fusion plasma and to propose a method for applying it to reversed field pinch (RFP).

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