H-Mode operation in the START spherical tokamak
H-mode operation has been achieved in high current (I(p)>200 kA) plasmas in the START spherical tokamak for both neutral-beam-injection-heated and Ohmic discharges. The transition to H mode features the development of well-defined edge pedestals in density and temperature, which signifies the formation of an edge-transport barrier, and associated edge-localized modes. Recent operation at plasma currents exceeding 250 kA shows that these features are accompanied by increases in energy confinement time. This is the first clear demonstration of the H-mode regime in a spherical tokamak.
Sykes
A
EURATOM/UKAEA Fusion Association, Culham Science Centre, Abingdon, Oxfordshire OX14 3DB, United Kingdom.
Akers
RJ
Appel
LC
Carolan
PG
Connor
JW
Conway
NJ
Counsell
GF
Dnestrovskij
A
Dnestrovskij
YN
Gryaznevich
M
Helander
P
Nightingale
MP
Ribeiro
C
Roach
CM
Tournianski
M
Walsh
MJ
Wilson
HR