Atelier pôle système solaire avril 2013

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1 Ludivine Leclercq 1, François Leblanc 2, Ronan Modolo 1, Lucile Turc 3 1 Université Versailles Saint Quentin, LATMOS, IPSL-CNRS, France 2 Université Pierre et Marie Curie, LATMOS, IPSL-CNRS, France 3 LPP, Ecole Polytechnique-CNRS-UPMC, France Atelier pôle système solaire avril 2013

2 Our understanding of Creation of exospheric particles Credits : X.Jia and M.Kivelson

3 Our understanding of Composition and structure Credits : X.Jia and M.Kivelson

4 Our understanding of Composition and structure Credits : X.Jia and M.Kivelson

5 Our understanding of Composition and structure Credits : X.Jia and M.Kivelson

6 Our 3D multispecies parallel model Monte Carlo methods : to follow particles that are ejected from the surface with a velocity following a distribution function. Parallelization using a domain decomposition method (MPI) a few days of calculations (64 CPU) against a few weeks in sequential.

7 Our 3D multispecies parallel model Considered species H 2 O, H 2, O 2, H, O, OH Spherical Grid ( cells) Surface temperature (Orton et al. 1996) T = 80K (nightside) T max = 150K Fluxes (Marconi 2007) Sputtering : Species Flux (s 1 cm 2 ) H 2 O O Sublimation at subsolar point: Species Flux (s 1 cm 2 ) H 2 O O 2 0

8 Our 3D multispecies parallel model Considered species H 2 O, H 2, O 2, H, O, OH Spherical Grid ( cells) Surface temperature (Orton et al. 1996) T = 80K (nightside) T max = 150K Chemistry Electron impact : at latitudes above 45 n e = 70cm 3 16 reactions Photo-ionization and Photodissociation : everywhere except in the shadow of Ganymede 17 reactions

9 Density profiles SSL=10 (subsolar region)

10 Density profiles SSL=90 (polar region)

11 Density of H 2 O H 2 O density in the subsolar/antisolar plane (left panel) and the terminator plane (right panel)

12 Collisions of H 2 O Ganymede presents a local atmosphere in the subsolar region

13 Collisions of H 2 O

14 JUICE local density during GCO 200 km phase

15 In the shadow of Jupiter

16 Conclusion are consistent with results of Marconi s model (2007). are also consistent with observations of HST and Galileo spacecraft. Perspectives To couple with a magnetospheric model.

17 Parallelization

18 Photodissociation and photo-ionization Reaction Rate (in s 1 ) Excess energy (ev) 1 H+hν H + +e H2+hν H+H H2+hν H + 2 +e H2+hν H+H + +e O+hν O + +e OH+hν O+H OH+hν OH + +e H 2 O+hν H+OH H 2 O+hν H 2 +O H 2 O+hν H+H+O H 2 O+hν H+OH + +e H 2 O+hν H 2 +O + +e H 2 O+hν OH+H + +e H 2 O+hν H 2 O + +e O 2 +hν O+O O 2 +hν O + 2 +e O 2 +hν O+O + +e

19 Electron impact Reaction Rate (in cm 3 s 1 ) Excess energy (ev) 18 H+e H + +e+e H 2 +e H+H+e H 2 +e H + 2 +e+e H 2 +e H + +H+e+e O+e O + +H+e+e OH+e O+H+e OH+e OH + +e H 2 O+e OH+H+e H 2 O+e H 2 +O+e H 2 O+e OH+H + +e+e H 2 O+e H+OH + +e+e H 2 O+e H 2 +O + +e+e H 2 O+e H 2 O + +e+e O 2 +e O+O+e O 2 +e O + 2 +e+e O 2 +e O+O + +e+e