Kivelson M G, Bargatze L F, Khurana K K, Southwood D J, Walker R J, Coleman P J
Science. 1993 Jul 16;261(5119):331-4. doi: 10.1126/science.261.5119.331.
Two large magnetic field rotations were recorded by the spacecraft Galileo 1 minute before and 2 minutes after its closest approach to the asteroid Gaspra. The timing and the geometry of the field changes suggest a connection with Gaspra, and the events can be interpreted as the result of the draping of the solar wind field around a magnetospheric obstacle. Gaspra's surface field is inferred to be within an order of magnitude of Earth's surface field, and its magnetic moment per unit mass is in the range observed for iron meteorites and highly magnetized chondrites. The location of the magnetic signatures suggests that perturbations are carried by waves in the magnetosonic-whistler mode with wavelengths between electron and ion gyro radii.
在航天器“伽利略号”最接近小行星加斯普拉之前1分钟和之后2分钟，记录到了两次大的磁场旋转。磁场变化的时间和几何形状表明与加斯普拉存在联系，这些事件可被解释为太阳风磁场围绕磁层障碍物形成悬垂的结果。据推断，加斯普拉的表面磁场与地球表面磁场相差不超过一个数量级，其单位质量的磁矩处于铁陨石和高磁化球粒陨石所观测到的范围内。磁特征的位置表明，扰动是由磁声波-哨声波模式下波长介于电子和离子回旋半径之间的波携带的。
