# How to Calculate the Magnetic and Electric Field

Could someone show me a real world example of how to calculate the Magnetic and Electric Field around the Sun or a Planet.
$$\vec{B} = \nabla * \vec{A} = (B_x, B_y,B_z)$$
$$\vec{E} = -\nabla*\phi-\frac{\partial \vec{A}}{\partial t} = (E_x,E_y,E_z)$$

UltrafastPED
Gold Member
For these equations you must first know the value of the vector potential, $$\vec{A}$$, and the electric potential, $$\phi$$.

How do you solve for ##\vec{A}## and ##\phi## for a planet or star acting like a dipole or current loop? For the sun the equations only are valid every 11 years or so because the polarity reverses. Also the earth does not have a true North North Pole it is somewhere in Siberia.

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Does anyone know where there is a list by date of Gaussian coefficients from the IAGA and IGRF(more recent then 2000).
They look like this ##g^m_n## and ##h^m_n##

UltrafastPED