By pointing one’s right thumb along the direction of the current, the direction of the magnetic field can by found by curving one’s fingers around the wire. The strength of the magnetic field depends on the current I in the wire and r, the distance from the wire.
Keeping this in consideration, what is the magnetic field of a wire?
The magnetic field is strongest in the area closest to the wire, and its direction depends upon the direction of the current that produces the field, as illustrated in this interactive animation. Presented in the tutorial is a straight wire with a current flowing through it.