Role of NBI fuelling in contributing to density peaking between the ICRH and NBI identity plasmas on JET
Journal article, 2022

Density peaking has been studied between an ICRH and NBI identity plasma in JET. The comparison shows that 8 MW of NBI heating/fueling increases the density peaking by a factor of two, being R/L (n) = 0.45 for the ICRH pulse and R/L (n) = 0.93 for the NBI one averaged radially over rho (tor) = 0.4, 0.8. The dimensionless profiles of q, rho *, upsilon *, beta (n) and T (i)/T (e) approximate to 1 were matched within 5% difference except in the central part of the plasma (rho (tor) < 0.3). The difference in the curvature pinch (same q-profile) and thermo-pinch (T (i) = T (e)) between the ICRH and NBI discharges is virtually zero. Both the gyro-kinetic simulations and integrated modelling strongly support the experimental result where the NBI fuelling is the main contributor to the density peaking for this identity pair. It is to be noted here that the integrated modeling does not reproduce the measured electron density profiles, but approximately reproduces the difference in the density profiles between the ICRH and NBI discharge. Based on these modelling results and the analyses, the differences between the two pulses in impurities, fast ions (FIs), toroidal rotation and radiation do not cause any such changes in the background transport that would invalidate the experimental result where the NBI fuelling is the main contributor to the density peaking. This result of R/L (n) increasing by a factor of 2 per 8 MW of NBI power is valid for the ion temperature gradient dominated low power H-mode plasmas. However, some of the physics processes influencing particle transport, like rotation, turbulence and FI content scale with power, and therefore, the simple scaling on the role of the NBI fuelling in JET is not necessarily the same under higher power conditions or in larger devices.

particle transport modelling

NBI fuelling

dimensioness identity plasma

density peaking

particle transport

Author

T. Tala

Technical Research Centre of Finland (VTT)

F. Eriksson

Culham Science Centre

P. Mantica

National Research Council of Italy (CNR)

A. Mariani

University of Milano-Bicocca

A. Salmi

Technical Research Centre of Finland (VTT)

E. R. Solano

Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (Ciemat)

I. S. Carvalho

University of Lisbon

A. Chomiczewska

Institute of Plasma Physics & Laser Microfusion (IPPLM)

E. Delabie

Culham Science Centre

J. Ferreira

University of Lisbon

Emil Fransson

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

L. Horvath

Culham Science Centre

P. Jacquet

Culham Science Centre

D. King

Culham Science Centre

A. Kirjasuo

Technical Research Centre of Finland (VTT)

S. Leerink

Aalto University

E. Lerche

TEC Partner

C. Maggi

Culham Science Centre

M. Marin

Dutch Institute for Fundamental Energy Research (DIFFER)

M. Maslov

Culham Science Centre

S. Menmuir

Culham Science Centre

R. B. Morales

Culham Science Centre

V Naulin

Technical University of Denmark (DTU)

M. F. F. Nave

University of Lisbon

Hans Nordman

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

C. Perez von Thun

Institute of Plasma Physics & Laser Microfusion (IPPLM)

P. A. Schneider

Max Planck Society

M. Sertoli

Tokamak Energy Ltd

K. Tanaka

National Institutes of Natural Sciences

Nuclear Fusion

0029-5515 (ISSN) 1741-4326 (eISSN)

Vol. 62 6 066008

Implementation of activities described in the Roadmap to Fusion during Horizon 2020 through a Joint programme of the members of the EUROfusion consortium (EUROfusion)

European Commission (EC) (EC/H2020/633053), 2014-01-01 -- 2019-01-01.

Subject Categories

Energy Engineering

Other Physics Topics

Fusion, Plasma and Space Physics

DOI

10.1088/1741-4326/ac5667

More information

Latest update

4/19/2022