Owing to the strong magnetic field in the magnetosphere, the magnetic field configuration essentially satisfies the approximation of the force-freefield.
由于磁层内部的磁场很强，其位形基本满足无作用力磁场近似。
2
Using the multistep implicit scheme, a numerical study was made to reveal the influence of linear force-freefield to the spontaneous reconnection of current sheets.
采用二维三分量磁流体力学数值模拟方法，研究了线性无力场对电流片的自发重联的影响。
3
When the magnetic field deviates from potential or force-freefield, the field-aligned current can be produced, and it relates closely with the intensity and lifetime of ducts.