A region of the upper atmosphere that surrounds the earth, extends out for thousands of miles, and is dominated by the earth's magnetic field so that charged particles ate trapped in it.

(围绕地球的)磁力层(地球大气层外的外圈，厚数千英里，受地球磁场控制)。

A region that surrounds a celestial body (as a planet) and is comparable of the earth's magnetosphere in trapping charged particles.

围绕其他天体的磁力层。