论文标题
地球电流板对太阳风湍流演变的影响
Influence of the heliospheric current sheet on the evolution of solar wind turbulence
论文作者
论文摘要
使用融合了扩展的盒子模型（EBM）的MHD模拟，研究了Heliosper潮流板（HCS）对太阳风中Alfvénic湍流进化的影响。模拟表明，在HCS附近，湍流的alfvénicities降低了，这表现为较低的归一化交叉螺旋性和较大的磁能过量。数值结果通过使用OMNI数据的超插度分析支持，该数据表明，HCS周围血浆板内的归一化交叉螺旋性降低，并且HCS中心的过量磁能显着增强。我们的仿真结果表明，HCS周围的Alfvénicity的减少是由于径向磁场的减弱以及背景磁场中横向梯度的影响。湍流中的磁能过量可能是由于速度和磁场之间的Alfvénic相关性丧失以及在球形扩展的太阳风中相对于磁能的横向动能的更快衰减。
The effects of the heliospheric current sheet (HCS) on the evolution of Alfvénic turbulence in the solar wind are studied using MHD simulations incorporating the expanding-box-model (EBM). The simulations show that near the HCS, the Alfvénicity of the turbulence decreases as manifested by lower normalized cross helicity and larger excess of magnetic energy. The numerical results are supported by a superposed-epoch analysis using OMNI data, which shows that the normalized cross helicity decreases inside the plasma sheet surrounding HCS, and the excess of magnetic energy is significantly enhanced at the center of HCS. Our simulation results indicate that the decrease of Alfvénicity around the HCS is due to the weakening of radial magnetic field and the effects of the transverse gradient in the background magnetic field. The magnetic energy excess in the turbulence may be a result of the loss of Alfvénic correlation between velocity and magnetic field and the faster decay of transverse kinetic energy with respect to magnetic energy in a spherically expanding solar wind.
