A Study of Jupiter's Radio Emission Mechanism by the Simultaneous Advanced Observations of Jupiter's Radio and Infrared Aurora Emissions

木星十分制射电发射的频率-时间动态光谱在几个不同的时间尺度上显示出一个复杂的结构。在几十秒的时间尺度上，其中一个特征光谱模式是Riihimaa在1968年发现的调制通道。我们开发了一个模型来解释它们产生的机制，其中自由参数可以调整，以提供与观测结果非常接近的拟合[Imai et al., 1992a,1992b,1997,2002]。在我们的模型中，我们提出了一个网格状干涉屏的存在，该干涉屏由位于木卫一轨道附近沿纵向方向的增强或耗尽等离子体密度的场对准柱组成。我们对奥卢、佛罗里达和南凯的宽带光谱仪观测到的Io-A和Io-B源调制通道进行了统计分析。利用调制通道方法，可以相对精确地测量出空心锥发射光束的锥半角值和Io-A和Io-B源的系统III源位置。两个光源测量的锥半角都在60度的3度范围内。测量到的III星源经度典型范围为：Io-A为130 ~ 205度，Io-B为125 ~ 215度。这些结果表明，Io-A和Io-B的放射性活跃区具有相同的源系统III经度。基于这些结果，我们能够首次使用3D计算机图形动画（http://jupiter.kochi-ct.jp/cg/）展示木星射电源的位置和光束的更真实的视图。这可以为研究木星十分制射电发射的机制提供非常重要的信息。

Frequency-time dynamic spectra of Jupiter's decametric radio emission display a complex structure on several different time scales. One of the characteristic spectral patterns on a time scale of a few tens of seconds are the modulation lanes discovered by Riihimaa in 1968. We developed a model for the mechanism responsible for their production in which the free parameters can be adjusted to provide a very close fit with the observations [Imai et al., 1992a,1992b,1997,2002]. In our model, we propose the existence of a grid-like interference screen composed of field-aligned columns of enhanced or depleted plasma density located along the longitudinal direction near Io's orbit.We made a statistical analysis of Io-A and Io-B source modulation lanes observed by wideband spectrographs at Oulu, Florida, and Nancay. Using the modulation lane method it was possible to make relatively precise measurements of the value of the cone half-angle of the hollow-cone emission beam and the System III source locations for the Io-A and Io-B sources. The measured cone half-angles for the two sources were both within about 3 degrees of 60 degrees. And the measured typical ranges of source System III longitude are 130 to 205 degrees for Io-A and 125 to 215 degrees for Io-B. These results show that the radio active regions of Io-A and Io-B are sharing the same source System III longitude. Based on these results, we are able to show for the first time a more realistic view of the location and beaming of Jupiter's radio sources using a 3D computer graphic animation (http://jupiter.kochi-ct.jp/cg/). This can provide a very important piece of information in the investigation of the mechanism responsible for Jupiter's decametric radio emission.