Magnetic Field Studies by Voyager 2: Preliminary Results at Saturn
Magnetic Field Studies by Voyager 2: Preliminary Results at Saturn
复制标题
旅行者 2 号磁场研究：土星的初步结果
作者：
N. Ness;M. Acuna;K. W. Behannon;L. Burlaga;J. Connerney;R. Lepping;F. Neubauer
旅行者2号对土星磁层和行星磁场的进一步研究证实了旅行者1号1980年观测所得的早期结果。磁场主要是中心偶极子（力矩= 0.21高斯- rs3；其中一个土星半径RS为60330公里）偏离旋转轴约0.8°。在最接近土星的时候，旅行者2号穿越了与旅行者1号互补的经纬度范围。有些令人惊讶的是，在数据或分析中没有发现北半球任何大规模磁异常的证据，这可能与土星千米辐射无线电发射的周期性调制有关。旅行者2号在正午子午线附近入站时，于18.5秒穿越了相对压缩的土星磁层的磁层顶。向外，在黎明子午线附近，磁层已经大大扩大，直到航天器到达48.4至50.9 RS，甚至可能更高，才观测到磁层顶边界。在46小时（土星自转4.5次）的时间里，磁场相对稳定和平滑，没有证据表明行星磁场中存在任何方位不对称或磁异常。因此，除了小的偶极子倾斜外，我们要了解土星千米辐射调制的基本来源，这是一个相当神秘的情况。
Further studies of the Saturnian magnetosphere and planetary magnetic field by Voyager 2 have substantiated the earlier results derived from Voyager 1 observations in 1980. The magnetic field is primarily that of a centered dipole (moment = 0.21 gauss-RS3; where one Saturn radius, RS, is 60,330 kilometers) tilted approximately 0.8� from the rotation axis. Near closest approach to Saturn, Voyager 2 traversed a kronographic longitude and latitude range that was complementary to that of Voyager 1. Somewhat surprisingly, no evidence was found in the data or the analysis for any large-scale magnetic anomaly in the northern hemisphere which could be associated with the periodic modulation of Saturnian kilometric radiation radio emissions. Voyager 2 crossed the magnetopause of a relatively compressed Saturnian magnetosphere at 18.5 RS while inbound near the noon meridian. Outbound, near the dawn meridian, the magnetosphere had expanded considerably and the magnetopause boundary was not observed until the spacecraft reached 48.4 to 50.9 RS and possibly beyond. Throughout the outbound magnetosphere passage, a period of 46 hours (4.5 Saturn rotations), the field was relatively steady and smooth showing no evidence for any azimuthal asymmetry or magnetic anomaly in the planetary field. We are thus left with a rather enigmatic situation to understand the basic source of Saturnian kilometric radiation modulation, other than the small dipole tilt.