在2005年对土卫五的近天体探测飞行中，科学家们期待利用美国宇航局的卡西尼宇宙飞船在月球表面拦截粒子的地方观察到读数下降。

During a 2005 flyby of Rhea, scientists working with NASA's Cassini spacecraft expected to see a dip in their readings where the moon's surface intercepted the particles.

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研究小组认为土卫五的大气环境是由高能粒子轰击土卫五冰封的表面，将土卫五表面的原子，分子和离子撞击到大气中而产生的。

The team believes the atmosphere is sustained by high energy particles bombarding its icy surface and kicking up atoms, molecules and ions into the atmosphere.

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土卫五在土星的磁场范围内运行，它在土星周围创建了一个带电粒子——离子和电子——泡沫。

Rhea orbits within Saturn's magnetic field, which creates a bubble of charged particles—ions and electrons—around the planet.

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