土星千米波辐射源及磁层内磁力线弯曲

本文提出一个模型，通过此模型得到土星千米波辐射源（Saturn's Kilometric Radiation Source）的分布.这个模型就是：磁层顶的开尔文-亥姆霍兹不稳定性（Kelvin Helmholtz Instability）会导致阿尔芬波沿着弯曲的磁力线传播到土星极区附近，并在这个过程中使土星电离层附近（1Rs高度，Rs为土星半径)的粒子加速沉降，发生回旋不稳定性（Cyclotron Maser Instability），进而产生R-X模式辐射的非寻常波（Extraordinary wave）.我们认为，极区发生回旋不稳定性的区域就是土星千米波辐射源的区域.本文求出了磁层顶附近开尔文-亥姆霍兹不稳定性发生在土星本地时（Saturn's Local Time）11 LT以前，得出了阿尔芬波沿磁力线传播到土星需要约383 min，求解出向阳面磁力线弯曲了约80°，最后得出土星千米波辐射源分布从黎明段的7～9 LT延伸到傍晚段的18 LT，并且黎明段分布的纬度比傍晚段低.

The source of Saturn's kilometric radiation and the magnetic field line's spirality

We put forward a model and deduce the distribution of Saturn's Kilometric Radiation (SKR) Source. The model is as follows, the Kelvin Helmholtz Instability (KHI) will generate kinds of wave, in which there is the Alfven wave. It will propagate to the Saturn's polar area by following the bending magnetic field line. It will also cause the Cyclotron Maser Instability (CMI) leading to the generation of extraordinary wave (R X mode) in the process. In our views, the region of the CMI, near the ionosphere of Saturn (1 Saturn radius above the polar area), is regarded as the same area as the Saturn's Kilometric Radiation Source.In this paper, we deduce that the KHI will appear before 11 LT (Saturn's Local Time), the Alfven wave will take 383 min to reach Saturn, the sunward magnetic line will bend almost 80°. Finally, we get the distribution of SKR source. It locates from 7～9 LT at a relatively lower latitude to 18 LT at the eveningside.