Sequential modelling of ICRF wave near RF fields and asymptotic RF sheaths description for AUG ICRF antennas

Jonathan Jacquot,Wouter Tierens,Volodymyr Bobkov,Wei Zhang,Jean-Marie Noterdaeme,Laurent Colas,J Hillairet

doi:10.1051/epjconf/201715703020

Abstract

A sequence of simulations is performed with RAPLICASOL and SSWICH to compare two AUG ICRF antennas. RAPLICASOL outputs have been used as input to SSWICH-SW for the AUG ICRF antennas. Using parallel electric field maps and the scattering matrix produced by RAPLICASOL, SSWICH-SW, reduced to its asymptotic part, is able to produce a 2D radial/poloidal map of the DC plasma potential accounting for the antenna input settings (total power, power balance, phasing). Two models of antennas are compared: 2-strap antenna vs 3-strap antenna. The 2D DC potential structures are correlated to structures of the parallel electric field map for different phasing and power balance. The overall DC plasma potential on the 3-strap antenna is lower due to better global RF currents compensation. Spatial proximity between regions of high RF electric field and regions where high DC plasma potentials are observed is an important factor for sheath rectification.

Highlights

A sequence of simulations is performed with RAPLICASOL and SSWICH to compare two ASDEX Upgrade (AUG) Ion Cyclotron Range of Frequencies (ICRF) antennas
The present paper presents simulations results e-mail: wouter.tierens@ipp.mpg.de for two ASDEX Upgrade antennas obtained with two codes:
RAPLICASOL (Radiofrequency wAve couPLing for Ion Cyclotron Antenna in Scrape-Off-Layer) to solve Maxwell’s equations in the cold plasma approximation without sheaths or any non-linear phenomenon

Summary

Introduction

RAPLICASOL (Radiofrequency wAve couPLing for Ion Cyclotron Antenna in Scrape-Off-Layer) to solve Maxwell’s equations in the cold plasma approximation without sheaths or any non-linear phenomenon. SSWICH (Self-consistent Sheaths and Waves for Ion Cyclotron Heating) to self-consistently determine the non linear response of the interaction of RF waves with the edge plasma (SOL)

RAPLICASOL

SSWICH-SW asymptotic

Simulations results interfacing SSWICH-SW with RAPLICASOL

Conclusions and discussion