We present a study of density fluctuations in coronal holes. We used a reduced magnetohydrodynamic (RMHD) model that incorporated observationally constrained density fluctuations to determine whether density fluctuations in coronal holes can enhance Alfvn wave reflection and dissipation, thereby heating coronal holes and driving the fast solar wind. We show results for two models of the background atmosphere. Each model is a solution of the momentum equation and includes the effects of wave pressure on the solar wind outflow. In the first model, the plasma density and Alfvn speed vary smoothly with height. Wave reflection is relatively weak in the smooth model, resulting in a low energy dissipation rate. In the second model, we include additional density fluctuations along the flux tube based on the observations. We find that density ρ fluctuations on the order of δρ/ρ ∼ 0.24 increase the Alfvn wave turbulence to levels sufficient to heat the open field regions in coronal holes.

我们对日冕洞中的密度波动进行了研究。我们使用了简化的磁流体动力学 (RMHD) 模型，该模型结合了观测约束的密度波动，以确定日冕孔中的密度波动是否可以增强 Alfvn 波的反射和耗散，从而加热日冕孔并驱动快速太阳风。我们展示了两种背景大气模型的结果。每个模型都是动量方程的解，包括波压对太阳风外流的影响。在第一个模型中，等离子体密度和 Alfvn 速度随高度平滑变化。光滑模型中的波反射相对较弱，导致能量耗散率较低。在第二个模型中，我们根据观察包括沿通量管的额外密度波动。我们发现密度δρ / ρ ∼ 0.24 数量级的ρ波动将 Alfvn 波湍流增加到足以加热日冕孔中的开放场区域的水平。