当真北和磁北相吻合的时候，确实存在一些被称为无偏线的地理线。
Geographical lines do exist where true north and magnetic north are aligned, and these are called agonic lines.
在磁层昼侧，若imf有南向分量，也就是和北向的地球磁场方向相反，则磁力线重连的效率最高。
Reconnection is most efficient when the IMF has a component that is directed southward-that is, opposite to the northward direction of the earth's magnetic field at the dayside of the magnetosphere.
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