[1] The anomalously weak observed magnetic field of Mercury is difficult to explain by appealing to crustal remanent magnetism or Earth-like dynamo mechanisms. Although the field is likely caused by a hydromagnetic dynamo, the field strength is far weaker than the characteristic strength expected from an active, strong field dynamo. Recent experimental work has shown that sources of compositional convection exist in mixtures of sulfur and iron at temperatures and pressures relevant to Mercury's core. The number and location of these iron "snow" zones is dependent on the sulfur content of the liquid portion of the core. We use a numerical dynamo model to show that the core states which include a snow zone midway through the core produce the observed field strength and expected field partitioning of the Mercurian magnetic field.Citation: Vilim, R., S. Stanley, and S. A. Hauck II (2010), Iron snow zones as a mechanism for generating Mercury's weak observed magnetic field,

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Recent theoretical and experimental evidence indicates that many of the materials that are thought to exist in the mantles of terrestrial exoplanets will metallize and become good conductors of electricity at mantle pressures. This allows for strong electromagnetic coupling of the core and the mantle in these planets. We use a numerical dynamo model to study the effect of a metallized lower mantle on the dynamos of terrestrial exoplanets using several inner core sizes and mantle conductivities. We find that the addition of an electrically conducting mantle results in stronger core-mantle boundary fields because of the increase in magnetic field stretching. We also find that a metallized mantle destabilizes the dynamo resulting in less dipolar, less axisymmetric poloidal magnetic fields at the core-mantle boundary. The conducting mantle efficiently screens these fields to produce weaker surface fields. We conclude that a conducting mantle will make the detection of extrasolar terrestrial magnetic fields more difficult while making the magnetic fields in the dynamo region stronger.