ELM Characteristics in MAST

Date

2004

Authors

Kirk, A.
Counsell, G.
Wilson, H. R.
Ahn, J. W.
Akers, R. J.
Martin, Richard
Hole, Matthew
Snyder, P. B.

Journal Title

Journal ISSN

Volume Title

Publisher

Institute of Physics Publishing

Abstract

Edge localized mode (ELM) characteristics in a large spherical tokamak (ST) with significant auxiliary heating are explored. High confinement is achieved in mega ampere spherical tokamak (MAST) at low ELM frequencies even though the ELMs exhibit many type III characteristics. These ELMs are associated with a reduction in the pedestal density but no significant change in the pedestal temperature or temperature profile, indicating that energy is convected from the pedestal region into the scrape-off layer. Power to the targets during an ELM arrives predominantly at the low field outboard side. ELM effluxes are observed up to 20 cm from the plasma edge at the outboard mid-plane and are associated with the radial motion of a feature at an average velocity of 0.75 km s-1. The target balance observed in MAST is potentially rather favourable for the ST since H-mode access is facilitated in a regime where ELM losses flow mostly to the large wetted area, outboard targets and, in addition, the target heat loads are reduced by an even distribution of power between the upper and lower targets.

Description

Keywords

Keywords: Edge localized mode; Large spherical tokamak; Radial motion; Charged particles; Frequencies; Plasma density; Plasma heating; Tokamak devices; Plasma confinement

Citation

Source

Plasma Physics and Controlled Fusion

Type

Journal article

Book Title

Entity type

Access Statement

License Rights

Restricted until

2037-12-31