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The magnitude of Earth's magnetic field at its surface ranges from 25 to 65 μT (0.25 to 0.65 G). [3] As an approximation, it is represented by a field of a magnetic dipole currently tilted at an angle of about 11° with respect to Earth's rotational axis, as if there were an enormous bar magnet placed at that angle through the center of Earth.
The following examples are listed in the ascending order of the magnetic-field strength. 3.2 × 10 −5 T (31.869 μT) – strength of Earth's magnetic field at 0° latitude, 0° longitude; 4 × 10 −5 T (40 μT) – walking under a high-voltage power line [9] 5 × 10 −3 T (5 mT) – the strength of a typical refrigerator magnet
A magnetic field (sometimes called B-field [1]) is a physical field that describes the magnetic influence on moving electric charges, electric currents, [2]: ch1 [3] and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and to the magnetic field.
The most common description of the electromagnetic field uses two three-dimensional vector fields called the electric field and the magnetic field.These vector fields each have a value defined at every point of space and time and are thus often regarded as functions of the space and time coordinates.
The magnetic field of a magnetic dipole has an inverse cubic dependence in distance, so its order of magnitude at the earth surface can be approximated by multiplying the above result with (R outer core ⁄ R Earth) 3 = (2890 ⁄ 6370) 3 = 0.093 , giving 2.5×10 −5 Tesla, not far from the measured value of 3×10 −5 Tesla at the equator.
The Earth's magnetic field protects the Earth from the deadly solar wind and has long been used for navigation. It originates in the fluid motions of the outer core. [24] The magnetic field in the upper atmosphere gives rise to the auroras. [26] Earth's dipole axis (pink line) is tilted away from the rotational axis (blue line).
New research indicates the sun’s magnetic field originates much closer to the surface than previously thought, a finding that could help predict periods of extreme solar storms like the ones ...
In all units, it is convenient to employ two types of magnetic field, B and H, as well as the magnetization M, defined as the magnetic moment per unit volume. The magnetic induction field B is given in SI units of teslas (T). B is the magnetic field whose time variation produces, by Faraday's Law, circulating electric fields (which the power ...