1. Lower Ip Long Pulse H+ITB Advanced Scenarios
C. Kessel*, A. Hubbard
*Princeton Plasma Physics Laboratory
C-MOD Ideas Forum, December 13-15, 2007

2. Goals Run Days
Examine lower Ip discharges to obtain higher boostrap current and higher non-inductive current fractions
Determine energy confinement in the lower Ip plasmas with ICRF power scan
Examine the benefits of longer Ip rampup times to control the q-profile with and without LHCD in the rampup -- density control to maximize effect of LHCD
Extend the pulse lengths to maximize the number of current relaxation times and to allow for development of modulation/control techniques in the advanced scenarios
Produce a reliable ITB formation approach
Search for strong current profile features in ITB plasmas

3. Low Ip Long Pulse H+ITB Advanced Scenarios
Establish lower Ip ramps at different ramp rates, to 600, 450 and 300 kA, and more reliable H+ITB formation -- document q-profile and loop voltage, both with/without LH injection in the ramp
H+ITB-mode
H-mode
n(0) Ip
PICoff
PICon
PLH
100
500
750
time, ms

4. Lower Ip Long Pulse H+ITB Advanced Scenarios
TSC simulation of Ip =450 kA H and H+ITB mode based on
H+ITB
H-mode
Up-down symmetric, no structure
PICoff

5. H+ITB H-mode T = 1.5 s Strong density peaking
H+ITB results in higher Vsurf due to lower Te weakening the impact of higher Ibootstrap