Tidally induced lateral variations of Io's interior
Tidally induced lateral variations of Io's interior
复制标题
潮汐引起木卫一内部的横向变化
DOI：
10.1016/j.icarus.2019.05.001
复制
发表时间：
2020
期刊：
影响因子：
3.2
通讯作者：
B. Vermeersen
中科院分区：
文献类型：
--
作者：
T. Steinke;H. Hu;D. Höning;W. Wal;B. Vermeersen
卫星和最近对木卫一表面的地面观测揭示了持续的热点和突然的高强度事件的特定空间模式。木卫一的主要生热机制是潮汐耗散，潮汐耗散被认为是不均匀地分布在木卫一的地幔和软流圈内。问题来了，木卫一不均匀的热量产生会在多大程度上导致内部和地表火山活动的长波变化。我们研究了两种不同的初始球对称粘弹性流变结构产生的耗散模式，这与大地测量的观测结果是一致的。用有限元模型计算了时间平均潮汐产热量的空间分布。而第一种流变结构只在上粘性层产生热量(软流圈-加热型)，第二种流变结构导致更均匀的散热模式(混合加热型)，潮汐加热发生在深部地幔和软流圈。为了将产热与内部温度和熔体分布联系起来，我们使用了地幔对流的稳态标度定律和一个简单的熔体迁移模型。由此产生的长波热不均一性强烈地依赖于初始潮汐耗散模式、对流层厚度、地幔粘度以及岩浆和对流热输送之间的比率。对于软流层加热模式，可以保持高达190 K峰间差的强横向温度信号，而对于混合加热模式，厚对流层内的对流可以将横向温度变化减小到<；1 K，如果地幔粘度足够低的话。以岩浆热传输为主的模型更好地保存了潮汐消散的长波模式，受到了青睐，因为它们更好地解释了木卫一的厚壳。本文提出的方法也可以用来研究任意内部加热模式对木卫一火山活动模式的影响。
Satellite and recent Earth-based observations of Io's surface reveal a specific spatial pattern of persisting hotspots and sudden high-intensity events. Io's major heat producing mechanism is tidal dissipation, which is thought to be non-uniformly distributed within Io's mantle and asthenosphere. The question arises to what extent Io's non-homogeneous heat production can cause long-wavelength variations in the interior and volcanic activity at the surface. We investigate dissipation patterns resulting from two different initially spherical symmetric visco-elastic rheological structures, which are consistent with geodetic observations. The spatial distributions of the time-averaged tidal heat production are computed by a finite element model. Whereas for the first rheological structure heat is produced only in the upper viscous layer (asthenosphere-heating model), the second rheological structure results in a more evenly distributed dissipation pattern (mixed-heating model) with tidal heating occurring in the deep mantle and the asthenosphere. To relate the heat production to the interior temperature and melt distribution, we use steady-state scaling laws of mantle convection and a simple melt migration model. The resulting long-wavelength thermal heterogeneities strongly depend on the initial tidal dissipation pattern, the thickness of the convective layer, the mantle viscosity, and the ratio between magmatic and convective heat transport. While for the asthenosphere-heating model a strong lateral temperature signal with up to 190 K peak-to-peak difference can remain, convection within a thick convective layer, as for the mixed-heating model, can reduce the lateral temperature variation to <1 K, if the mantle viscosity is sufficiently low. Models with a dominating magma heat transport preserve the long-wavelength pattern of tidal dissipation much better and are favoured, because they are better to explain Io's thick crust. The approach presented here can also be applied to investigate the effect of an arbitrary interior heating pattern on Io's volcanic activity pattern.
静止盖地球的宜居性
影响因子：
6.5
作者：
Godolt;Stracke;Ruedas;Grenfell;Höning;Nikolaou;Breuer
通讯作者：
Breuer