The term 'external-origin geomagnetic field' refers to the magnetic field that originates outside the Earth's core. This field is produced due to the interactions between the solar wind and the Earth's magnetic field. Synonyms for this term include 'interplanetary magnetic field' (IMF), 'solar wind magnetic field', and 'magnetospheric magnetic field.' The IMF refers to the magnetic field carried by the solar wind, while the solar wind magnetic field refers to the magnetic component of the solar wind. The magnetospheric magnetic field, on the other hand, describes the magnetic field that shields the Earth from the harmful effects of the solar wind. These synonyms all refer to the same phenomenon, but focus on different aspects of the external-origin geomagnetic field.