Super-Earths are extremely common among the numerous exoplanets that have been discovered. The high pressures and temperatures in their interiors are likely to lead to long-lived magma oceans. If their electrical conductivity is sufficiently high, the mantles of Super-Earth would generate their own magnetic fields. With ab initio simulations, we show that upon melting, the behavior of typical mantle silicates changes from semi-conducting to semi-metallic. The electrical conductivity increases and the optical properties are substantially modified. Melting could thus be detected with high-precision reflectivity measurements during the short time scales of shock experiments. We estimate the electrical conductivity of mantle silicates to be of the order of 100 Ω−1 cm−1, which implies that a magnetic dynamo process would develop in the magma oceans of Super-Earths if their convective velocities have typical values of 1 mm/s or higher. We predict exoplanets with rotation periods longer than 2 days to have multipolar magnetic fields.
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机译：在已发现的众多系外行星中，超地球极为普遍。其内部的高压和高温可能导致长寿命的岩浆海洋。如果它们的电导率足够高，那么超级地球的幔子就会产生自己的磁场。通过从头算的模拟，我们表明，融化后，典型的地幔硅酸盐的行为从半导体变为半金属。导电率增加并且光学性质被显着改变。因此，可以在冲击实验的短时间内通过高精度反射率测量来检测融化。我们估计地幔硅酸盐的电导率大约为100Ω −1 cm −1 ，这暗示着磁发电机过程将在印度洋的岩浆海中发展。超地球的对流速度的典型值是1 mm / s或更高。我们预测旋转周期超过2天的系外行星将具有多极磁场。
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