Woodfield E E, Glauert S A, Menietti J D, Horne R B, Kavanagh A J, Shprits Y Y
British Antarctic Survey Cambridge UK.
University of Iowa Iowa IA USA.
Geophys Res Lett. 2022 Feb 16;49(3):e2021GL096213. doi: 10.1029/2021GL096213. Epub 2022 Jan 27.
Plasmaspheric hiss waves at the Earth are well known for causing losses of electrons from the radiation belts through wave particle interactions. At Saturn, however, we show that the different plasma density environment leads to acceleration of the electrons rather than loss. The ratio of plasma frequency to electron gyrofrequency frequently falls below one creating conditions for hiss to accelerate electrons. The location of hiss at high latitudes (>25°) coincides very well with this region of very low density. The interaction between electrons and hiss only occurs at these higher latitudes, therefore the acceleration is limited to mid to low pitch angles leading to butterfly pitch angle distributions. The hiss is typically an order of magnitude stronger than chorus at Saturn and the resulting acceleration is rapid, approaching steady state in one day at 0.4 MeV at L = 7 and the effect is stronger with increasing L-shell.
地球的等离子层嘶声波以通过波粒相互作用导致辐射带中的电子损失而闻名。然而，在土星，我们发现不同的等离子体密度环境导致电子加速而非损失。等离子体频率与电子回旋频率之比经常低于1，这为嘶声波加速电子创造了条件。嘶声波在高纬度地区（>25°）的位置与这个非常低密度的区域非常吻合。电子与嘶声波之间的相互作用仅发生在这些较高纬度地区，因此加速仅限于中低俯仰角，导致出现蝴蝶俯仰角分布。在土星，嘶声波通常比合声波强一个数量级，由此产生的加速很快，在L = 7时，0.4兆电子伏特的电子在一天内接近稳态，并且随着L壳层增加，这种效应更强。
