Writing this answer has got me thinking.
You can estimate the exhaust velocity of an ion engine using
$$\frac{v}{c} = \sqrt{\frac{2E}{m_0 c^2}}. $$
Choose $E=$ 100 keV and $m_0 c^2=$ 931 MeV times 50 to 200 AMU and you get between 0.2 and 0.1% of the speed of light, which at 600 to 300 km/sec is way beyond escape velocity of the Earth or the Sun.
If this happens in LEO, or on a deep space mission, where would these ions end up? Are they still trapped by the Earths' magnetic field, or the interplanetary magnetic field, or would they just go shooting straight out of the solar system and into interplanetary space? Would they instead thermalize somewhere in the solar system through collisions?