The partition of irreversible heating between ions and electrons in compressively driven (but subsonic) collisionless turbulence is investigated by means of nonlinear hybrid gyrokinetic} simulations. We derive a prescription for the ion-to-electron heating ratio $Q_\rmi/Q_\rme$ as a function of the compressive-to-Alfv'enic driving power ratio $P_\compr/P_\AW$, of the ratio of ion thermal pressure to magnetic pressure $\beta_\rmi$, and of the ratio of ion-to-electron background temperatures $T_\rmi/T_\rme$. It is shown that $Q_\rmi/Q_\rme$ is an increasing function of $P_\compr/P_\AW$. When the compressive driving is sufficiently large, $Q_\rmi/Q_\rme$ approaches $\simeq P_\compr/P_\AW$. This indicates that, in turbulence with large compressive fluctuations, the partition of heating is decided at the injection scales, rather than at kinetic scales. Analysis of phase-space spectra shows that the energy transfer from inertial-range compressive fluctuations to sub-Larmor-scale kinetic Alfv'en waves is absent for both low and high $\beta_\rmi$, meaning that the compressive driving is directly connected to the ion entropy fluctuations, which are converted into ion thermal energy. This result suggests that preferential electron heating is a very special case requiring low $\beta_\rmi$ and no, or weak, compressive driving. Our heating prescription has wide-ranging applications, including to the solar wind and to hot accretion disks such as M87 and Sgr A*.

中文翻译：

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压缩驱动天体旋涡动荡中的离子与电子加热

通过非线性混合动力动力学模拟研究了压缩驱动（但亚音速）无碰撞湍流中离子与电子之间不可逆加热的分配。我们推导出一个处方用于离子到电子加热比$ Q_ \ RMI / Q_ \ RME $作为压缩到Alfv'enic驱动功率比的函数$ P_ \ COMPR / P_ \ AW $的比率，离子热压与磁压$ \ beta_ \ rmi $的关系，以及离子对电子本底温度的比率$ T_ \ rmi / T_ \ rme $。显示$ Q_ \ rmi / Q_ \ rme $是$ P_ \ compr / P_ \ AW $的递增函数。当压缩驱动足够大时，$ Q_ \ rmi / Q_ \ rme $接近$ \ simeq P_ \ compr / P_ \ AW $。这表明，在具有大的压缩波动的湍流中，加热的分配是在注入尺度而不是动力学尺度决定的。相空间谱分析表明，对于低和高$ \ beta_ \ rmi $，都不存在从惯性范围压缩涨落到亚Larmor级动力学Alfv'en波的能量转移，这意味着压缩驱动是直接连接的离子熵涨落，转化为离子热能。此结果表明优先电子加热是一种非常特殊的情况，需要低的\\ beta_ \ rmi $而且没有或没有压缩驱动。我们的加热处方具有广泛的应用，包括太阳风和热吸积盘，例如M87和Sgr A *。