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Geomagnetic pole
The geomagnetic poles are antipodal points where the axis of a best-fitting dipole intersects the surface of Earth. This theoretical dipole is equivalent to a powerful bar magnet inside the Earth. The best-fitting dipole generally results from a theoretical magnet that is not precisely at the center of the Earth, this is known as the eccentric dipole model. For modern-day Earth (unlike most planets in our Solar System) a simpler centered dipole model is a close enough approximation to be used for some purposes. There are historical periods when the Earth's field did not resemble a dipole at all.
In contrast to the geomagnetic poles, the observed magnetic poles or dip poles of the Earth are places where the actual magnetic field intersects the surface. The magnetic poles are not antipodal: asymmetries in the earth and variations in its magnetic field mean that the line on which they lie does not pass through Earth's center.
Owing to the motion of fluid in the Earth's outer core, the magnetic field is constantly moving, in what is called geomagnetic secular variation. This leads to short-term changes in the magnetic and geomagnetic poles.
Although the geomagnetic poles average out local variations in the magnetic field, they are useful in geophysics as an efficient and more slowly-changing approximation than the magnetic poles. For example, since it is the entire field that determines the positions of auroras, the geomagnetic poles are an effective model for predicting their behavior.
As a first-order approximation, the Earth's magnetic field can be modeled as a simple dipole (like a bar magnet), tilted about 9.6° with respect to the Earth's rotation axis (which defines the Geographic North and Geographic South Poles) and centered at the Earth's center. This is known as the centered dipole model of the field. The North and South Geomagnetic Poles are the antipodal points where the axis of this theoretical dipole intersects the Earth's surface. Thus, unlike the actual magnetic poles, the geomagnetic poles always have an equal degree of latitude and supplementary degrees of longitude respectively (2017: Lat. 80.5°N, 80.5°S; Long. 72.8°W, 107.2°E). If the Earth's magnetic field were a perfect dipole, the field lines would be vertical to the surface at the Geomagnetic Poles, and they would align with the North and South magnetic poles, with the North Magnetic Pole at the south end of dipole.
As a better second-order approximation, the field can be modeled as a dipole somewhere other than the center of the Earth. This is known as the eccentric dipole model. Even this approximation is imperfect; the magnetic poles migrate a greater distance each year than the geomagnetic poles, and usually lie hundreds of kilometers apart.
Like the North Magnetic Pole, the North Geomagnetic Pole attracts the north pole of a bar magnet and so is in a physical sense actually a magnetic south pole. It is the center of the 'open' magnetic field lines which connect to the interplanetary magnetic field and provide a direct route for the solar wind to reach the ionosphere. As of 2020[update], it was located at 80°39′N 72°41′W / 80.65°N 72.68°W, on Ellesmere Island, Nunavut, Canada, compared to 2015, when it was located at 80°22′N 72°37′W / 80.37°N 72.62°W, also on Ellesmere Island.
The South Geomagnetic Pole is the point where the axis of this best-fitting tilted dipole intersects the Earth's surface in the southern hemisphere. As of 2020[update], it is located at 80°39′S 107°19′E / 80.65°S 107.32°E, whereas in 2005, it was calculated to be located at 79°44′S 108°13′E / 79.74°S 108.22°E, near Vostok Station.
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Geomagnetic pole AI simulator
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Geomagnetic pole
The geomagnetic poles are antipodal points where the axis of a best-fitting dipole intersects the surface of Earth. This theoretical dipole is equivalent to a powerful bar magnet inside the Earth. The best-fitting dipole generally results from a theoretical magnet that is not precisely at the center of the Earth, this is known as the eccentric dipole model. For modern-day Earth (unlike most planets in our Solar System) a simpler centered dipole model is a close enough approximation to be used for some purposes. There are historical periods when the Earth's field did not resemble a dipole at all.
In contrast to the geomagnetic poles, the observed magnetic poles or dip poles of the Earth are places where the actual magnetic field intersects the surface. The magnetic poles are not antipodal: asymmetries in the earth and variations in its magnetic field mean that the line on which they lie does not pass through Earth's center.
Owing to the motion of fluid in the Earth's outer core, the magnetic field is constantly moving, in what is called geomagnetic secular variation. This leads to short-term changes in the magnetic and geomagnetic poles.
Although the geomagnetic poles average out local variations in the magnetic field, they are useful in geophysics as an efficient and more slowly-changing approximation than the magnetic poles. For example, since it is the entire field that determines the positions of auroras, the geomagnetic poles are an effective model for predicting their behavior.
As a first-order approximation, the Earth's magnetic field can be modeled as a simple dipole (like a bar magnet), tilted about 9.6° with respect to the Earth's rotation axis (which defines the Geographic North and Geographic South Poles) and centered at the Earth's center. This is known as the centered dipole model of the field. The North and South Geomagnetic Poles are the antipodal points where the axis of this theoretical dipole intersects the Earth's surface. Thus, unlike the actual magnetic poles, the geomagnetic poles always have an equal degree of latitude and supplementary degrees of longitude respectively (2017: Lat. 80.5°N, 80.5°S; Long. 72.8°W, 107.2°E). If the Earth's magnetic field were a perfect dipole, the field lines would be vertical to the surface at the Geomagnetic Poles, and they would align with the North and South magnetic poles, with the North Magnetic Pole at the south end of dipole.
As a better second-order approximation, the field can be modeled as a dipole somewhere other than the center of the Earth. This is known as the eccentric dipole model. Even this approximation is imperfect; the magnetic poles migrate a greater distance each year than the geomagnetic poles, and usually lie hundreds of kilometers apart.
Like the North Magnetic Pole, the North Geomagnetic Pole attracts the north pole of a bar magnet and so is in a physical sense actually a magnetic south pole. It is the center of the 'open' magnetic field lines which connect to the interplanetary magnetic field and provide a direct route for the solar wind to reach the ionosphere. As of 2020[update], it was located at 80°39′N 72°41′W / 80.65°N 72.68°W, on Ellesmere Island, Nunavut, Canada, compared to 2015, when it was located at 80°22′N 72°37′W / 80.37°N 72.62°W, also on Ellesmere Island.
The South Geomagnetic Pole is the point where the axis of this best-fitting tilted dipole intersects the Earth's surface in the southern hemisphere. As of 2020[update], it is located at 80°39′S 107°19′E / 80.65°S 107.32°E, whereas in 2005, it was calculated to be located at 79°44′S 108°13′E / 79.74°S 108.22°E, near Vostok Station.
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