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Ion versus Electron Heating in Compressively Driven Astrophysical Gyrokinetic Turbulence
Physical Review X ( IF 11.6 ) Pub Date : 2020-12-11 , DOI: 10.1103/physrevx.10.041050 Y. Kawazura , A. A. Schekochihin , M. Barnes , J. M. TenBarge , Y. Tong , K. G. Klein , W. Dorland
Physical Review X ( IF 11.6 ) Pub Date : 2020-12-11 , DOI: 10.1103/physrevx.10.041050 Y. Kawazura , A. A. Schekochihin , M. Barnes , J. M. TenBarge , Y. Tong , K. G. Klein , W. Dorland
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 as a function of the compressive-to-Alfvénic driving power ratio , of the ratio of ion thermal pressure to magnetic pressure , and of the ratio of ion-to-electron background temperatures . It is shown that is an increasing function of . When the compressive driving is sufficiently large, approaches . 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 Alfvén waves is absent for both low and high , 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 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:
压缩驱动的天体动力回旋湍流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。我们推导了离子与电子加热比的规定 与Alfvénic压缩比的函数关系 ,离子热压与磁压之比 ,以及离子与电子背景温度之比 。结果表明 是...的增加功能 。当压缩驱动足够大时, 方法 。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。对相空间谱的分析表明,无论是低还是高,都没有从惯性范围的压缩涨落到亚Larmor级动力学Alfvén波的能量转移,意味着压缩驱动与离子熵涨落直接相关,离子涨落被转换为离子热能。该结果表明,优先电子加热是一种非常低的要求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 *。
更新日期:2020-12-11
中文翻译:
压缩驱动的天体动力回旋湍流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。我们推导了离子与电子加热比的规定 与Alfvénic压缩比的函数关系 ,离子热压与磁压之比 ,以及离子与电子背景温度之比 。结果表明 是...的增加功能 。当压缩驱动足够大时, 方法 。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。对相空间谱的分析表明,无论是低还是高,都没有从惯性范围的压缩涨落到亚Larmor级动力学Alfvén波的能量转移,意味着压缩驱动与离子熵涨落直接相关,离子涨落被转换为离子热能。该结果表明,优先电子加热是一种非常低的要求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 *。