Magnetic Dipole Field at Equator

\[B=\frac{\mu_0 m}{4\pi r^3}\]

Variables

Bmagnetic field strength at equator (T)

mu0vacuum permeability (H/m)

mmagnetic dipole moment (A·m²)

rdistance from dipole center (m)

Description

What is this formula?

This formula calculates the magnetic field strength produced by a magnetic dipole at a point located on its equatorial plane. It is commonly used in geophysics, magnetism, and planetary magnetic field analysis.

When to use it

Use this formula when evaluating the magnetic field generated perpendicular to the dipole axis, such as near the Earth's magnetic equator or around bar magnets and magnetic particles.

Example

A magnetic dipole has a magnetic moment of 250 A·m². Calculate the magnetic field at a point located 0.4 m from the center on the equatorial plane.

Data:

m = 250 A·m²

r = 0.4 m

mu0 = 4π × 10^-7 H/m

Formula:

B = (mu0*m)/(4*pi*r^3)

Substitution:

B = ((4*pi*10^-7)*250)/(4*pi*(0.4^3))

Result:

B = 3.91 × 10^-4 T

Applications

- Earth's magnetic field modeling

- Magnetic anomaly studies

- Magnet design

- Planetary science

- Magnetic sensor calibration