Image »An Ion Orbits Around The Equator in The Earth's Magnetic Field« download
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Sharing and adapting of the illustration is allowed with the reference "Alexander Fufaev (fufaev.org)"
A positively charged particle orbits the Earth in a westward direction along the equator. The circular path is due to the earth's magnetic field, which has approximately a constant value at the equator.
This particle experiences a Lorentz force (magnetic force) directed towards the center of the earth, which you can easily understand with the right-hand rule.
