论文标题
在波数空间中的动力学尺度的质子和电子之间的磁能传递和分布
Magnetic Energy Transfer and Distribution between Protons and Electrons for Alfvénic Waves at Kinetic Scales in Wavenumber Space
论文作者
论文摘要
湍流耗散被认为是宇宙等离子体中加热和加速的主要来源。交替的当前类似焦耳的项，$ \langleΔjj\cdotΔe\ rangle $，用于测量电磁（EM）磁场和颗粒之间的能量转移。由于电场取决于参考框架，因此在哪个框架中计算$ \langleΔjj\cdotΔe\ rangle $是一个重要问题。我们计算了波形空间中的比例依赖性能量传递速率谱，并研究了两个参考帧中的电场波动：平均散装流量框中的$ΔE$，在本地散装流量框架中（非惯性参考框架）中的$ΔE'$。考虑到alfvénic波，我们发现$ \langleΔjj\cdotΔe^\ prime \ prime \ rangle $，它忽略了磁场能量阻尼速率（$2γδb^2 $），根据linearearearearemaxwell-iise $ is $ is $ \ cd cd cd cd cd cd cd cd cd cd cd cdectemant $ cd cd cd cd cd cdect与$2γδb^2 $在vavenumber空间$（k_ \ parallel，k_ \ perp）$相同，其中$γ$是线性阻尼速率。在1 AU处太阳风的典型条件下，我们在理论计算中发现，场能主要转化为质子动能，使残留的电子部分的残留次要部分。尽管电子在垂直于平均磁场的方向上获得能量，但它们在平行方向上返回其动能的很大一部分。磁场波动可以在平行和垂直的自由度之间传递粒子能量。因此，$ \langleδj_\并行\cdotΔe_\ Parallele \ rangle $和$ \langleΔj_\ perp \cdotΔe_\ perp \ perp \ rangle $不能完全描述能量转移，分别分别沿并行方向和垂直方向描述。
Turbulent dissipation is considered a main source of heating and acceleration in cosmological plasmas. The alternating current Joule-like term, $\langleδj \cdot δE\rangle$, is used to measure the energy transfer between electromagnetic (EM) fields and particles. Because the electric field depends on the reference frame, in which frame to calculate $\langleδj\cdot δE\rangle$ is an important issue. We compute the scale-dependent energy transfer rate spectrum in wavevector space, and investigate the electric-field fluctuations in two reference frames: $δE$ in the mean bulk flow frame and $δE'$ in the local bulk flow frame (non-inertial reference frame). Considering Alfvénic waves, we find that $\langleδj\cdotδE^\prime\rangle$, which neglects the contribution of work done by the ion inertial force, is not consistent with the magnetic field energy damping rate ($2γδB^2$) according to linear Maxwell-Vlasov theory, while $\langleδj\cdot δE\rangle$ is exactly the same as $2γδB^2$ in wavenumber space $(k_\parallel, k_\perp)$, where $γ$ is the linear damping rate. Under typical conditions of solar wind at 1 au, we find in our theoretical calculation that the field energy is mainly converted into proton kinetic energy leaving the residual minor portion for electrons. Although the electrons gain energy in the direction perpendicular to the mean magnetic field, they return a significant fraction of their kinetic energy in the parallel direction. Magnetic-field fluctuations can transfer particle energy between the parallel and perpendicular degrees of freedom. Therefore, $\langleδj_\parallel\cdot δE_\parallel\rangle$ and $\langleδj_\perp\cdot δE_\perp\rangle$ cannot solely describe the energy transfer in parallel direction and perpendicular direction, respectively.
