Key parts of the ITER scenarios are determined by the capability of the proposed poloidal
field (PF) coil set. They include the plasma breakdown at low loop voltage, the current
rise phase, the performance during the flat top (FT) phase and a ramp down of the
plasma. The ITER discharge evolution has been verified in dedicated experiments. New
data are obtained from C-Mod, ASDEX Upgrade, DIII-D, JT-60U and JET. Results show
that breakdown for E-axis < 0.23-0.33 V m(-1) is possible unassisted (ohmic) for large
devices like JET and attainable in devices with a capability of using ECRH assist.
For the current ramp up, good control of the plasma inductance is obtained using a
full bore plasma shape with early X-point formation. This allows optimization of the
flux usage from the PF set. Additional heating keeps l(i)(3) < 0.85 during the ramp
up to q(95) = 3. A rise phase with an H-mode transition is capable of achieving l(i)(3)
< 0.7 at the start of the FT. Operation of the H-mode reference scenario at q(95)
similar to 3 and the hybrid scenario at q(95) = 4-4.5 during the FT phase is documented,
providing data for the l(i) (3) evolution after the H-mode transition and the li (3)
evolution after a back-transition to L-mode. During the ITER ramp down it is important
to remain diverted and to reduce the elongation. The inductance could be kept <= 1.2
during the first half of the current decay, using a slow I-p ramp down, but still
consuming flux from the transformer. Alternatively, the discharges can be kept in
H-mode during most of the ramp down, requiring significant amounts of additional heating.
