Synthetic X-ray Tomography Diagnostics for Tokamak Plasmas

A Jardin,Y Peysson,J Dankowski,M Scholz,J Bielecki,D Mazon,K Król

doi:10.1007/s10894-020-00250-9

Abstract

Tomography diagnostics represent an essential tool in tokamaks to infer the local plasma properties using line-integrated measurements from one or several cameras. In particular, soft X-rays (SXR) in the energy range 0.1–20 keV can provide valuable information on magnetohydrodynamic activity, magnetic equilibrium or impurity transport. Heavy impurities like tungsten (W) are a major source of concern due to significant radiation losses in the plasma core, thus they have to be kept under acceptable concentrations. Therefore, 2D SXR tomography diagnostics become crucial to estimate the W concentration profile in the plasma, quantify the W poloidal distribution and identify relevant impurity mitigation strategies. In this context, a synthetic diagnostic becomes a very valuable tool (1) to study the tomographic reconstruction capabilities, (2) to validate diagnostic design as well as (3) to assess the error propagation during the reconstruction process and impurity transport analysis. The goal of this contribution is to give some highlights on recent studies related to each of these three steps, for the development of SXR synthetic diagnostic tools in tokamak plasmas.

Highlights

In the context of an increasing world energy production based on limited fossil fuel reserves and with a doubling time of 30–40 years in the last century, e.g. from 6000 million tons of oil equivalent (Mtoe) in 1973 to more than 13,000 Mtoe in 2013 [1], controlled thermonuclear fusion could be the ideal candidate to fulfil the future energy demand
A synthetic diagnostic becomes a very valuable tool (1) to study the tomographic reconstruction capabilities, (2) to validate diagnostic design as well as (3) to assess the error propagation during the reconstruction process and impurity transport analysis. The goal of this contribution is to give some highlights on recent studies related to each of these three steps, for the development of soft X-rays (SXR) synthetic diagnostic tools in tokamak plasmas
Impurity density reconstruction and subsequent transport analysis

Summary

Introduction

In the context of an increasing world energy production based on limited fossil fuel reserves and with a doubling time of 30–40 years in the last century, e.g. from 6000 million tons of oil equivalent (Mtoe) in 1973 to more than 13,000 Mtoe in 2013 [1], controlled thermonuclear fusion could be the ideal candidate to fulfil the future energy demand. Reliable SXR diagnostic tools are essential to monitor the local impurity density, study W transport in the plasma core and identify actuators to avoid W central accumulation.

Results

Conclusion