Wave propagation in the upper convection zone

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Wave propagation in the upper convection zone

• Robert Cameron
• Laurent Gizon

Max Planck Institute for Solar System Research
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Outline

• The photosphere
• The wave code
• Sunspots

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Regimes of solar magneto-convection
sunspot
pore

• Local structuring
• -quiet Sun
• -plage
• -umbral dots
• Global structuring
• -pores
• -sunspots
• -flux emergence

plage
quiet Sun
G-band image KIS/VTT, Obs. del Teide, Tenerife
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Linear, ideal equations
Currently no background flows are allowed.
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BCs and IC

• Upper BC vertical components of shear stress
  tensor vanishes
• Lower perturbation vanishes
• Sides periodic
• IC arbitrary, but eg right moving f-mode wave
  packet.

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Numerical scheme

• Spectral (fourier) in the horizontal directions.
• Uses FFTW.
• Finite difference (2-step Lax-Wendroff) in the
  Vertical (This will probably change soon.)
• Status preliminary results, some test cases.

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We will (at some point) provide

• Wave code
• Sample background
• You will need to make your own interesting
  atmospheres. (Possibly eg using fully non-linear
  backgrounds from Stein and Nordlund).

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Sunspot models
From Rempel and Schüssler
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Preliminary Simulation
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Observations from Gizon
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Working on

• Background velocities.
• Top BC
• Extending the atmosphere upwards
• What to do with high Alfven velocities

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Quiet Sun simulations
MURaM Quiet sun granulation box extended upwards
with Model S atmosphere.
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HELAS

• Wants to collect and make available modeling
  tools.
• What type of tools are interesting? (Please
  discuss this afternoon and not during my question
  time.)
• Working (essential) and documented (please?).
• Maintenance is probably unreasonable, but perhaps
  we should have a users (where should the
  apostrophe go?) blog for each tool?