Thermal Convection in the Core of Ganymede Inferred from Liquid Eutectic Fe-FeS Electrical Resistivity at High Pressures

The electrical resistivity of solid and liquid Fe-FeS was measured using a 4-wire resistance technique at pressures from 2-5 GPa and the thermal conductivity was calculated using the Wiedemann-Franz Law from the electrical measurements. The results were used to estimate the pressure-dependent eutectic temperatures of the system and adiabatic conductive heat flow at the top of a molten Fe-FeS core model of Ganymede, which showed that thermal convection is permissible as a dynamo power source.

本研究采用四线电阻测量技术，在2~5吉帕斯卡（GPa）的压力条件下，测定了固态与液态铁-硫化亚铁（Fe-FeS）体系的电阻率，并基于维德曼-夫兰兹定律（Wiedemann-Franz Law）由电学测量数据计算得到热导率。基于上述测试结果，本研究估算了该体系的压力依赖性共晶温度，以及木卫三（Ganymede）熔融铁-硫化亚铁核模型顶层的绝热传导热流，结果表明热对流可作为该体系的发电机动力源。