Mercury

Something similar was also detected on Mars a few years ago. One researcher commented: "The sudden intensification of a ring current causes the main phase of a magnetic storm." Coronal mass ejections from the sun were identified as a cause.
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An international team of scientists has proved that Mercury, our solar system's smallest planet, has geomagnetic storms similar to those on Earth, says Science Daily.

Their finding, a first, answers the question of whether other planets, including those outside our solar system, can have geomagnetic storms regardless of the size of their magnetosphere or whether they have an Earth-like ionosphere.

The research by scientists in the United States, Canada and China includes work by Hui Zhang, a space physics professor at the University of Alaska Fairbanks Geophysical Institute.

Their finding, a first, answers the question of whether other planets, including those outside our solar system, can have geomagnetic storms regardless of the size of their magnetosphere or whether they have an Earth-like ionosphere.

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