main magnetic field

例句：

1. 1. The main magneticfield lines are aligned in a particulardirection.
   主磁场线以特定方向排列。
2. 2.The discovery of the main magnetic field hasrevolutionized our understanding of the universe.
   发现主磁场已经彻底改变了我们对宇宙的理解。
3. 3.The main magnetic field is responsible for themovement of charged particles in the Earth's atmosphere.
   主磁场负责地球大气中带电粒子的运动。