Institute of Space Weather, School of Atmospheric Physics, Nanjing University of Information Science and Technology, Nanjing, 210044, China.
Sci Rep. 2023 May 7;13(1):7409. doi: 10.1038/s41598-023-34082-2.
A parametric study on the energy transfer of the solar wind across the magnetopause entering the magnetosphere is conducted using a global magnetohydrodynamic numerical simulation. The characteristics of the mechanical and electromagnetic energy distribution under the dawn-dusk interplanetary magnetic fields (IMFs) are investigated by analyzing magnetic reconnection and viscous effect, and compared with the radial and north-south IMFs. It is shown that (1) the interactions at the magnetopause and the transfer of energy across this boundary move in relation to the IMF orientation. (2) For the duskward IMF, the mechanical energy flow clearly enters the equatorial and low-latitude regions on the dayside, and the electromagnetic energy flow has a small inflow on the equatorial and low latitudes of the dayside. A significant energy inflow appears on the dawn side in the northern hemisphere and the dusk side in the southern hemisphere near the polar cusp. (3) The energy distribution characteristics across the magnetopause under dawn-dusk IMFs are mirror symmetric about the [Formula: see text] plane. (4) For a magnetic field of 5 nT, the electromagnetic energy input under the dawn-dusk IMFs is twice as large as the mechanical energy and the electromagnetic energy under the radial IMF, which is five times as large as the electromagnetic energy during the pure northward IMF, but only half as large as the electromagnetic energy under the pure southward IMF. The mechanical energy input under dawn-dusk IMFs has the same magnitude as that under radial and north-south IMFs. The magnitude of the energy transfer rate for the dawn IMF and dusk IMF (about 3.5%) is between 1.71% for the northward IMF and 4.95% for the southward IMF, but higher than 2.22% for the radial IMF. The Akasofu-type energy-coupling formula, [Formula: see text], underestimates the energy input from the solar wind under [Formula: see text] dominated IMF.
采用全球磁流体力学数值模拟方法对穿越磁层进入磁层的磁层顶的太阳风能量传递进行了参数研究。通过分析磁重联和粘性效应，研究了日侧行星际磁场（IMF）在机械和电磁能量分布特征，并与径向和南北向 IMF 进行了比较。结果表明：（1）磁层顶的相互作用和穿过此边界的能量传递与 IMF 方向有关。（2）对于向西的 IMF，机械能流明显进入昼侧赤道和低纬区，电磁能流在昼侧赤道和低纬区有少量流入。在北半球黎明侧和南半球黄昏侧极尖附近，在昼侧出现明显的能量流入。（3）日侧和夜侧 IMF 下的磁层顶能量分布特征关于[Formula: see text]面是镜像对称的。（4）对于 5 nT 的磁场，日侧和夜侧 IMF 下的电磁能量输入是径向 IMF 下的机械能和电磁能量的两倍，是纯北向 IMF 下的五倍，是纯南向 IMF 下的一半。日侧和夜侧 IMF 下的机械能输入与径向和南北向 IMF 下的机械能输入相同。黎明 IMF 和黄昏 IMF 的能量传递率（约 3.5%）在北向 IMF 的 1.71%和南向 IMF 的 4.95%之间，但高于径向 IMF 的 2.22%。Akasofu 型能量耦合公式[Formula: see text]低估了主导 IMF 为[Formula: see text]时太阳风的能量输入。
