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Can someone explain me in simple terms where and what are the magnetic, geographic and geomagnetic poles?

Some sites say that magnetic north pole is in the south and thus it attracts the south pole of the magnetic needle while some say the north pole of the needle points south. In each place, I seem to get a different angle between the magnetic and geographical axis (10°, 11°, 17° etc.). And I don't get clearly what the geomagnetic pole is. I'm utterly confused, please help me out.

This question slightly addresses my doubt but the answers contradict each other.

Thanks in advance.

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The geographic poles are the North Pole and the South Pole of the Earth. These are not the actual magnetic poles, they are the axial poles. The magnetic poles are the actual poles of the Earth's magnetic field, but are not antipodal as they do not pass through the Earth's center. The geomagnetic poles are antipodal as they pass through the center of the Earth to represent a dipole bar magnet at Earths center. The magnetic north pole attracts the north pole of a bar magnet, or compass needle, so the magnetic north pole is actually the south pole of Earth's magnetic field. You may get contradictory locations for the magnetic and geomagnetic poles as they move slightly over time.

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  • $\begingroup$ Where exactly will the north pole point - to the magnetic North or to the geomagnetic North? $\endgroup$ – Shub Sep 23 '20 at 4:23
  • $\begingroup$ A compass needle will point to the magnetic north pole, I will make an edit to clarify this. $\endgroup$ – Adrian Howard Sep 23 '20 at 5:45
  • $\begingroup$ Thanks, I understood. I'd be glad if you add a diagram in your answer and organise it with some headings. $\endgroup$ – Shub Sep 23 '20 at 5:48
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The North geographic pole is where the effective axis of rotation meets the surface at the North end of the earth. The North (seeking) pole of a magnet is the end which swings toward the North (if its mount allows it to turn). The magnetic field of a magnet emerges from the North (seeking) pole, loops around, and reenters at the “South pole”. The magnetic field of the earth emerges from a North magnetic pole, which is near (but not at) the South geographic pole, loops around and reenters at a South magnetic pole which is near (but not at) the North geographic pole. I have just learned that there are two types of magnetic pole. A compass locates a magnetic pole on the surface of the earth,but the field in space directs the charged particles which cause the aurora toward a geomagnetic pole. The two do not coincide.

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  • $\begingroup$ But this figure shows that the north geomagnetic pole is in North: images.app.goo.gl/RDXxrK7AiqUCQ8657 $\endgroup$ – Shub Sep 23 '20 at 4:19
  • $\begingroup$ People may refer to the magnetic pole up north as the north magnetic pole, but from the point of view of physics it is a south magnetic pole. $\endgroup$ – R.W. Bird Sep 23 '20 at 12:45
  • $\begingroup$ Thanks! I found the relation of Aurora and geomagnetic poles in your answer quite helpful :) $\endgroup$ – Shub Sep 23 '20 at 13:22
  • $\begingroup$ No, charged particles would travel (roughly) towards the North Magnetic Pole because they respond to local fields, not a theoretical best fit to the global field. $\endgroup$ – A. Newell Sep 23 '20 at 23:22
  • $\begingroup$ I was quoting an article which I found on line. $\endgroup$ – R.W. Bird Sep 24 '20 at 12:19
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Although an answer has been accepted, there are lots of errors and ambiguities in the above answers. First of all, when you talk about getting a local angle between the magnetic and geographic axis, that is the magnetic declination. At most points on Earth, your compass does not point to any of the North geographic pole, the North Magnetic Pole or the geomagnetic North pole.

The three kinds of poles would coincide if the source of Earth's field were a very tiny but powerful bar magnet with its South pole pointing at geographic North. A field with this geometry is called a dipolar field (see Magnetic dipole). If the bar were tilted away from the rotation axis, then clearly magnetic and geographic North would not coincide, but everywhere on Earth our compasses would point to the North magnetic pole.

In reality, Earth's magnetic field is very complex, but it has modest deviations from a dipolar field. If you measure the field all over Earth and find the best fitting dipole field, its North pole at Earth's surface is the geomagnetic North pole.

If the field were dipolar, then at the geomagnetic North pole, a compass needle that could rotate in all directions would point straight down. This is referred to as the North Magnetic Pole. Since it is not, the North Magnetic Pole is at a different location. Also, the deviations from a dipolar field are complex, so as you move a compass around Earth, the declination changes. Finally, the field is always changing, so the declination is changing everywhere, as are the magnetic poles. Fortunately for navigation, these changes are slow.

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