Pedestal Stability Analysis on MAST in preparation for MAST-U

Pedestal Stability Analysis on MAST in preparation for MAST-U

Pedestal Stability Analysis on MAST in preparation for MAST-U 150 150 UKAEA Opendata
UKAEA-CCFE-PR(21)04

Pedestal Stability Analysis on MAST in preparation for MAST-U

In preparation for the upcoming MAST-U campaign, pedestal stability of spherical tokamaks is revisited by investigating standard H-mode discharges on MAST. As a step beyond previous studies, both ion and electron profiles are used for obtaining equilibria and a diverse set of pedestals is evaluated. Stability analysis with the ELITE and CGYRO codes shows that MAST pedestals are constrained by medium range peeling-ballooning and kinetic ballooning modes, with most unstable modes ranging from n=25 to n=45. In discharges with a steep q profile at the edge a larger number of poloidal harmonics is excited for each toroidal mode. A comparison with discharges on DIII-D with matched shape and similar non-dimensional parameters indicates that the increased shear due to lower aspect ratio stabilizes peeling mode drive.

Collection:
Journals
Journal:
Nuclear Fusion
Publisher:
IOP (Institute of Physics)