Saturn's Magnetic Field and Magnetosphere
Saturn's Magnetic Field and Magnetosphere
复制标题
土星的磁场和磁层
作者：
E. J. Smith;L. Davis;Douglas E. Jones;Paul J. Coleman;D. Colburn;P. Dyal;C. Sonett
先驱者号土星矢量氦磁力仪探测到土星的弓形激波和磁层顶，并提供了行星场的准确特征。赤道表面场为0.20高斯，比根据地球和木星的尝试缩放所预期的小3到5倍。磁偶极轴和土星自转轴之间的倾斜角< 1 °，这是一个令人惊讶的小值。测量的球谐分析显示四极矩与偶极矩的比率<10%，表明磁场比地球或木星的磁场更均匀，并且与土星具有相对较小的核心相一致。外磁层的磁场显示出系统偏离偶极磁场，主要是中午附近磁场的压缩和黎明附近与电流片相关的赤道方向。土卫六与旋转的磁层相互作用产生的磁流体尾流似乎已经被观测到。
The Pioneer Saturn vector helium magnetometer has detected a bow shock and magnetopause at Saturn and has provided an accurate characterization of the planetary field. The equatorial surface field is 0.20 gauss, a factor of 3 to 5 times smaller than anticipated on the basis of attempted scalings from Earth and Jupiter. The tilt angle between the magnetic dipole axis and Saturn's rotation axis is < 1�, a surprisingly small value. Spherical harmonic analysis of the measurements shows that the ratio of quadrupole to dipole moments is < 10 percent, indicating that the field is more uniform than those of the Earth or Jupiter and consistent with Saturn having a relatively small core. The field in the outer magnetosphere shows systematic departures from the dipole field, principally a compression of the field near noon and an equatorial orientation associated with a current sheet near dawn. A hydromagnetic wake resulting from the interaction of Titan with the rotating magnetosphere appears to have been observed.