P218 The viscosity of Super-Earths and implications for their magnetic field generation Vlada...
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Transcript of P218 The viscosity of Super-Earths and implications for their magnetic field generation Vlada...
![Page 1: P218 The viscosity of Super-Earths and implications for their magnetic field generation Vlada Stamenković, Doris Breuer and Tilman Spohn Joint Planetary.](https://reader036.fdocuments.us/reader036/viewer/2022070415/56649e8f5503460f94b93a14/html5/thumbnails/1.jpg)
P218The viscosity of Super-Earths and
implications for their magnetic field generation
Vlada Stamenković, Doris Breuer and Tilman SpohnJoint Planetary Interior Physics Research Group
of The University of Münster and the IPR DLR Berlin
![Page 2: P218 The viscosity of Super-Earths and implications for their magnetic field generation Vlada Stamenković, Doris Breuer and Tilman Spohn Joint Planetary.](https://reader036.fdocuments.us/reader036/viewer/2022070415/56649e8f5503460f94b93a14/html5/thumbnails/2.jpg)
PROBLEM:
• We want to model the thermal evolution of Super-Earths!– Processes: Plate tectonics, Magnetic fields, etc
• But have only thermal properties, especially viscosity, for small pressures.• Viscosity controls the thermal evolution of planets and depends on
temperature T and pressure P!
• PRESSURE IS EXTREMELY IMPORTANT FOR SUPER-EARTHS AND HAS BEEN IGNORED SO FAR!
( , ) exp effE P VP T
RT
P218
![Page 3: P218 The viscosity of Super-Earths and implications for their magnetic field generation Vlada Stamenković, Doris Breuer and Tilman Spohn Joint Planetary.](https://reader036.fdocuments.us/reader036/viewer/2022070415/56649e8f5503460f94b93a14/html5/thumbnails/3.jpg)
PROBLEM:
• We want to model the thermal evolution of Super-Earths!– Processes: Plate tectonics, Magnetic fields, etc
• But have only thermal properties, especially viscosity, for small pressures.• Viscosity controls the thermal evolution of planets and depends on
temperature T and pressure P!
• PRESSURE IS EXTREMELY IMPORTANT FOR SUPER-EARTHS AND HAS BEEN IGNORED SO FAR!
*
( , ) exp effE P VP T
RT
THEREFORE:We include pressure dependence!
& Implications for mantle convection and dynamos!
P218
![Page 4: P218 The viscosity of Super-Earths and implications for their magnetic field generation Vlada Stamenković, Doris Breuer and Tilman Spohn Joint Planetary.](https://reader036.fdocuments.us/reader036/viewer/2022070415/56649e8f5503460f94b93a14/html5/thumbnails/4.jpg)
RESULTS 1: Viscosity
• NOW WE GET:– Large mantle viscosities and increasing with depth (adiabate)
Old
New
P218
![Page 5: P218 The viscosity of Super-Earths and implications for their magnetic field generation Vlada Stamenković, Doris Breuer and Tilman Spohn Joint Planetary.](https://reader036.fdocuments.us/reader036/viewer/2022070415/56649e8f5503460f94b93a14/html5/thumbnails/5.jpg)
RESULTS 2: NO convection
• Due to the large viscosity we get:– Super-Earths are not fully convecting planets!
P218
NO CONVECTION
![Page 6: P218 The viscosity of Super-Earths and implications for their magnetic field generation Vlada Stamenković, Doris Breuer and Tilman Spohn Joint Planetary.](https://reader036.fdocuments.us/reader036/viewer/2022070415/56649e8f5503460f94b93a14/html5/thumbnails/6.jpg)
RESULTS 2: NO convection
• Due to the large viscosity we get: – Super-Earths are not fully convecting planets!
P218
NO CONVECTION
CONTRARY TO ALL OLDER MODELS,
WHERE FULL CONVECTION ASSUMED!
![Page 7: P218 The viscosity of Super-Earths and implications for their magnetic field generation Vlada Stamenković, Doris Breuer and Tilman Spohn Joint Planetary.](https://reader036.fdocuments.us/reader036/viewer/2022070415/56649e8f5503460f94b93a14/html5/thumbnails/7.jpg)
RESULTS 3: NO magnetic fields?
• High viscosity and Low-lid thermally insulate the core• There is not enough power Φ to drive the magnetic dynamo!
P218
0(8 10 )Gyrs
Earth Super-Earth
0
B