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Earth's magnetic field, predominantly dipolar at its surface, is distorted further out by the solar wind. This is a stream of charged particles leaving the Sun's corona and accelerating to a speed of 200 to 1000 kilometres per second. They carry with them a magnetic field, the interplanetary magnetic field (IMF).
Magnetosphere. A rendering of the magnetic field lines of the magnetosphere of the Earth. In astronomy and planetary science, a magnetosphere is a region of space surrounding an astronomical object in which charged particles are affected by that object's magnetic field. [1][2] It is created by a celestial body with an active interior dynamo.
Dynamo theory describes the process through which a rotating, convecting, and electrically conducting fluid acts to maintain a magnetic field. This theory is used to explain the presence of anomalously long-lived magnetic fields in astrophysical bodies. The conductive fluid in the geodynamo is liquid iron in the outer core, and in the solar ...
Magnetic reconnection is a breakdown of "ideal-magnetohydrodynamics" and so of "Alfvén's theorem" (also called the "frozen-in flux theorem") which applies to large-scale regions of a highly-conducting magnetoplasma, for which the Magnetic Reynolds Number is very large: this makes the convective term in the induction equation dominate in such regions.
Magnetopause. Abrupt boundary between a magnetosphere and the surrounding plasma. Artistic rendition of the Earth's magnetopause. The magnetopause is where the pressure from the solar wind and the planet's magnetic field are equal. The position of the Sun would be far to the left in this image. The magnetopause is the abrupt boundary between a ...
e. The Van Allen radiation belt is a zone of energetic charged particles, most of which originate from the solar wind, that are captured by and held around a planet by that planet's magnetosphere. Earth has two such belts, and sometimes others may be temporarily created.
The dipole model of the Earth's magnetic field is a first order approximation of the rather complex true Earth's magnetic field. Due to effects of the interplanetary magnetic field (IMF), and the solar wind, the dipole model is particularly inaccurate at high L-shells (e.g., above L=3), but may be a good approximation for lower L-shells.
Magnetosphere particle motion. A sketch of Earth's magnetic field representing the source of Earth's magnetic field as a magnet The North Pole of Earth is near the top of the diagram, the South Pole near the bottom. Notice that the South Pole of that magnet is deep in Earth's interior below Earth's North Magnetic Pole.