Title: Simulations of entropy rain-driven convection Show Chinese title

Title: 熵雨驱动对流的模拟

Abstract: Context: The paradigm of convection in solar-like stars is questioned based on recent solar observations. Aims: The primary aim is to study the effects of surface-driven entropy rain on convection zone structure and flows. Methods: Simulations of compressible convection in Cartesian geometry with non-uniform surface cooling are used. The cooling profile includes localized cool patches that drive deeply penetrating plumes. Results are compared with cases with uniform cooling. Results: Sufficiently strong surface driving leads to strong non-locality and a largely subadiabatic convectively mixed layer. In such cases the net convective energy transport is done almost solely by the downflows. The spatial scale of flows decreases with increasing number of cooling patches for the vertical flows whereas the horizontal flows still peak at large scales. Conclusions: To reach the plume-dominated regime with a predominantly subadiabatic bulk of the convection zone requires significantly more efficient entropy rain than what is realized in simulations with uniform cooling. It is plausible that this regime is realized in the Sun but that it occurs on scales smaller than those resolved currently. Current results show that entropy rain can lead to largely mildly subadiabatic convection zone, whereas its effects for the scale of convection are more subtle. Show Chinese abstract

Abstract: 背景：基于最近的太阳观测，太阳类似恒星对流的范式受到质疑。 目标：主要目标是研究表面驱动的熵雨对对流区结构和流动的影响。 方法： 使用笛卡尔几何中可压缩对流的模拟，并带有非均匀表面冷却。 冷却剖面包括局部冷却斑块，这些斑块驱动深入的羽流。 结果与均匀冷却的情况进行比较。 结果：足够强的表面驱动会导致强烈的非局域性以及主要亚绝热的对流混合层。 在这种情况下，净对流能量传输几乎完全由下降流完成。 对于垂直流动，流动的空间尺度随着冷却斑块数量的增加而减小，而水平流动仍然在大尺度上达到峰值。 结论：要达到以羽流为主的对流区状态，其中大部分是对流区亚绝热，需要比目前均匀冷却模拟中实现的效率更高的熵雨。 有可能在太阳中实现了这种状态，但其发生在当前分辨率无法解析的小尺度上。 目前的结果表明，熵雨可以导致主要为轻微亚绝热的对流区，而对于对流尺度的影响则更为微妙。