Towards understanding reactor relevant tokamak pedestals
Journal article, 2021

The physics of the tokamak pedestal is still not fully understood, for example there is no fully predictive model for the pedestal height and width. However, the pedestal is key in determining the fusion power for a given scenario. If we can improve our understanding of reactor relevant pedestals we will improve our confidence in designing potential fusion power plants. Work has been carried out as part of a collaboration on reactor relevant pedestal physics. We report some of the results in detail here and review some of the wider work which will be reported in full elsewhere. First, we attempt to use a gyrokinetic-based calculation to eliminate the pedestal top density as a model input for Europed/EPED pedestal predictions. We assume power balance at the top of the pedestal, that is, the heat flux crossing the separatrix must be equal to the heat source at the top of the pedestal and investigate the consequences of this assumption. Unfortunately, the transport assumptions of the EPED model mean that this method does not discriminate between different pairs of density and temperature profiles for a given pressure profile. Second, we investigate the effects of non flux surface density on the bootstrap current. Third, type I ELMs will not be tolerable for a reactor relevant regime due to the damage that they are expected to cause to plasma facing components. In recent years various methods of running tokamak plasmas without large ELMs have been developed. These include small and no ELM regimes, the use of resonant magnetic perturbations and the use of vertical kicks. We discuss the quiescent H-mode here. Finally we give a summary and directions for future work.

MHD

tokamak

pedestal

Author

C. J. Ham

Culham Science Centre

A. Bokshi

Institute for Plasma Research India

D. Brunetti

Culham Science Centre

G. Bustos Ramirez

Swiss Federal Institute of Technology in Lausanne (EPFL)

B. Chapman

Culham Science Centre

J. W. Connor

Culham Science Centre

D. Dickinson

University of York

A. R. Field

Culham Science Centre

L. Frassinetti

Royal Institute of Technology (KTH)

Andreas Gillgren

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics, Extragalactic Astrophysics

J. P. Graves

Swiss Federal Institute of Technology in Lausanne (EPFL)

T. P. Kiviniemi

Aalto University

S. Leerink

Aalto University

B. McMillan

The University of Warwick

S. Newton

Culham Science Centre

S. Pamela

Culham Science Centre

C. M. Roach

Culham Science Centre

S. Saarelma

Culham Science Centre

J. Simpson

Culham Science Centre

S. F. Smith

Culham Science Centre

E. R. Solano

Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (Ciemat)

Pär Strand

Chalmers, Space, Earth and Environment, Astronomy and Plasmaphysics

A. J. Virtanen

Aalto University

Nuclear Fusion

0029-5515 (ISSN)

Vol. 61 9 096013

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) (633053), 2014-01-01 -- 2019-01-01.

Subject Categories

Energy Engineering

Other Physics Topics

Fusion, Plasma and Space Physics

DOI

10.1088/1741-4326/ac12e9

More information

Latest update

8/17/2021