1. Secondary divertor heat and particle flux
in support of ITER thermal load specifications
Baseline
Worst case
Proposer: R. A. Pitts (IO), MIT contact: B. LaBombard
Motivation
ITER’s burning plasma equilibria are expected to run reasonably close to double null
We know comparatively little about fluxes of heat and particles at the secondary divertor
Thermal loads have been defined for power handling design of upper blanket modules based on extrapolations from relatively sparse data and some modeling
The specified loads push some modules close to margins
We seek to consolidate our physics basis
drsep ~9 cm
drsep ~4 cm

2. Secondary divertor heat and particle flux
in support of ITER thermal load specifications
e.g. DIII-D
Proposer: R. A. Pitts (IO), MIT contact: B. LaBombard
Before ELM
Motivation
We do know, qualitatively, that the secondary divertor fluxes can be rather intense ….
e.g. JET
DIII-D #138219
Secondary strike
IR TV
During ELM
68193, 17 s
J. G. Watkins, IAEA 2010

3. Secondary divertor heat and particle flux
in support of ITER thermal load specifications
Proposer: R. A. Pitts (IO), MIT contact: B. LaBombard
Experimental approach
No ELM behaviour seen in SNL/SNU H-modes with strike points on lower, outer instrumented tiles  concentrate on EDA  perhaps a good proxy for mitigated ELM scenarios on ITER
Use SNU and place secondary divertor strike on instrumented tiles.
Look for:
Steady state q||(r) and target ne(r), Te(r) at secondary strike as function of:
Midplane drsep, density, input power, L-mode vs. H-mode
lq in EDA versus ELM-free H-mode periods
Study if possible particle flux turbulence at instrumented tiles (embedded LP) and compare with character found in far SOL (RCP). Also far SOL parallel flow
Experiments must be performed with ion BxB drift upwards, towards primary X-point. Cryopumping not necessary (if not required for plasma ops).
Probably up to two experimental sessions, including preparation.