Physics
Scientific paper
May 2004
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004agusmgp33a..02l&link_type=abstract
American Geophysical Union, Spring Meeting 2004, abstract #GP33A-02
Physics
1510 Dynamo Theories, 5440 Magnetic Fields And Magnetism, 6225 Mars, 8115 Core Processes (1507), 8147 Planetary Interiors (5430, 5724)
Scientific paper
Recent planetary missions to Mars have shown that there once was a very energetic dynamo acting in its liquid core and that this dynamo is now extinct. Two options concerning the timing of this dynamo are highly debated, either early or delayed. The early dynamo has the advantage of being readily explained by thermal convection, that stops when the heat flow across the core mantle boundary drops below that conducted down the adiabatic temperature gradient. The delayed dynamo is more difficult to explain in this framework, since it requires a non monotonic heat flow history. However, such a timing is required to explain lunar magnetism by dynamo action operating between 4 and 3 Ga in its core. Here we explore the possibility of a dynamo sustained by compositional convection, which is known to operate more efficiently than thermal convection in the Earth core. Compositional convection is triggered by the onset of crystallisation of an inner core if the composition of the core is on the iron rich side of the eutectic. The gradual growth of the inner core leads to a change of composition of the outer core, until the eutectic is reached, shutting down compositional convection. Using all available data on the phase diagram of iron alloys, in the range of pressure relevant to cores of Mars and the moon, we determine the conditions that make possible this scenario.
Andrault Denis
Labrosse Stephane
No associations
LandOfFree
Compositional Dynamo in Mars and the Moon does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Compositional Dynamo in Mars and the Moon, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Compositional Dynamo in Mars and the Moon will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1178215