Study of nonlinear kinetic effects in Stimulated Raman Scattering using semiLagrangian Vlasov codes

1
Study of nonlinear kinetic effects in Stimulated
Raman Scattering using semi-Lagrangian Vlasov
codes

• Alain Ghizzo1, P. Bertrand1, T.W. Johnston2,
• M. Albrecht-Marc1,T. Reveillé1
• 1. LPMIA, CNRS-UMR7040, Université Henri
  Poincaré, Nancy,
• BP 239, F-54506 Vandoeuvre, France
• 2. I.N.R.S. Energie et Matériaux, Varennes,
  Québec
• Alain.Ghizzo_at_lpmi.uhp-nancy.fr

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Topics

• Vlasov plasmas
• Vlasov codes and PIC codes
• Application I Resonant wave particle interaction
• Application II SRS-B in optical mixing
• Conclusions

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Topics

• Vlasov plasmas
• Vlasov codes and PIC codes
• Application I Resonant wave particle interaction
• Application II SRS-B in optical mixing
• Conclusions

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Introduction

• . Vlasov models have long been used to study
  collisionless plasmas.
• Vlasov codes powerful tool for studying in
  details the particle dynamics due to very fine
  resolution in phase space.
• Questions for applications
• Need for a kinetic model?
• PIC or Vlasov simulation?

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Vlasov plasmas collective effects
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Topics

• Vlasov plasmas
• Vlasov codes and PIC codes
• Application I Resonant wave particle interaction
• Application II SRS-B in optical mixing
• Conclusions

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Comparison PIC-Vlasov (1)
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Comparison PIC-Vlasov (2)
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Comparison PIC-Vlasov (3)
Prefer PIC
Prefer Vlasov
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Topics

• Vlasov plasmas
• Vlasov codes and PIC codes
• Application I Resonant wave particle interaction
• Application II SRS-B in optical mixing
• Conclusions

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Stimulated Raman Scattering
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SRS 3 mode coupling
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Three mode coupling a fluid description
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Three mode coupling a fluid description
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Three mode coupling a fluid description
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Time evolution pump scattered
Check the fluid predictions against a fully
kinetic Vlasov simulation
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Time evolution pump plasma
Poor Conservation !
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Phase space portraits (1)
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Phase space portraits (2)
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Phase space portraits (3)
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Accounting for  non fluid  particles
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Topics

• Vlasov plasmas
• Vlasov codes and PIC codes
• Application I Resonant wave particle interaction
• Application II SRS-B in optical mixing
• Conclusions

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SRS-B in the  kinetic  regime (1)

• SRS-B reflectivity presents a bursting behavior

• Nonlinear frequency shift - G.J. Morales and T.M.
  ONeil, PRL 28, 417 (1972) -

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SRS-B in the  kinetic  regime (2)
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Topics

• Vlasov plasmas
• Vlasov codes and PIC codes
• Application I Resonant wave particle interaction
• Application II SRS-B in optical mixing
• Conclusions

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Conclusions

• Vlasov codes as compared to PIC codes
• lack of numerical noise
• good resolution in phase space
• provided the dimension of velocity space is as
  low as possible.
• Kinetic effects in plasmas allow more phenomena
  than are found using only fluid theory with  ad
  hoc  kinetic damping.