1

0 1 2 3 4 5 60

1

2

3

4

5

6

167134 q95 vs q0

q9

5

q00 1 2 3 4 5 6 7 8

0

1

2

3

4

5

6

7

8

167062 q95 vs q0

q9

5

q0

GA PCS Design Studies for ITER Include Analytic Ideal MHD

Boundary and Real-time Error Field Correction Algorithm

• Approximate ideal MHD

stability boundary:

– Validated with DIII-D data

– Enables study of active control

to maintain stability, prevent

disruption

• Real-time Error Field Correction

– Extremum-Seeking algorithm

– Varies correction field amplitude

phase to maximize plasma

rotation

– Automatically finds optimal

correction (if enough rotation…)

EXS/P6-37 D.Humphreys/IAEA FEC Kyoto/October 2016

qa »1

q020

-0.5+2q0 + 0.2sin 4p q0 - 0.5[ ]( )

q95

q0 q0

Disrupts

Remains

stable

DIII-D Rampup Trajectories

#167062 #167134

Stable region

Stable

region