Recent Edge modeling on HL2A

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Recent Edge modeling on HL-2A
Pan Yudong
1. HL-2A SOL and divertor configuration.
2. HL-2A Simulation results. 1)Two divertor
Modes. 2) Parameters distributions at target
plate. 3. Next step plan.
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2D Multi Species Fluid Code
1.Assumptions ?The code models electrically
neutral and current-free plasma. ? Each ion
fluid is governed by a Navier-Stokes system of
equations. ? Coupling between the plasma species
occurs through ionization and recombination
process,inter-species friction,electric and
thermal forces and temperature equilibration. 2.
Multi species fluid codes ? Continuity. ?
Momentum balance. ? Radial diffusion. ?
Electron energy balance. ? Ion energy balance.
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HL-2A Divertor Configuration-2Dimension
Y
X
X

Y
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Re-cycling Operation Mode-Linear Mode
For HL-2A low density operation region, linear
recycling operation mode can be obtained. The
plasma with low density and higher temperature is
formed near the target plate.
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Re-cycling Operation Modes-High Recycling Mode
For HL-2A high density operation region, high
recycling operation mode can be obtained. The
plasma with high density and low temperature is
formed near the target plate.
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Conclusion(1)

• The electron density and temperatures in the
  SOL and divertor region have strong inhomogeneity
  along the magnetic surface.

High recycling mode is more suitable than linear
mode. 1) It can prevents the reverse transport
of the impurity. 2) It can form high-pressure
neutral hydrogen gas. 3) It is useful for the
puffing of the divertor. 4) The lower
temperature decreases the erosion on the target
plate.
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Distributions at the target plate
, ,
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Temperature, electron density distribution at the
target plate
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Heat load distribution at the target plate
The peak heat load will locate near the
separatrix strike point at the target plate.
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Distributions at Edge Plasma
High recycling
linear
Detach
Peak density and Peak temperatures at the target
plate changed with the edge density.
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Next Step Plan
1.linear -----high recycling-----detach Impurity
effect Detach Plasma
modelling. B2Eirene 2.The edge plasma physics
during the Supersonic Beam injection.
The high fueling efficiency a
significant cooling of the plasma edge, Lower
recycling ?
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Conclusion
? Simulation shows HL-2A can form different
re-cycling operation modes for different density
operation regions. Recycling modes can be
controlled by controlling plasma density at the
interface between modeling edge region and core
region. ?The parameters distributions at target
plate depend on the recycling modes. But the peak
heat load will locate near the separatrix strike
point at the target plate.