Abstract: For a steady current-carrying tightly wound thick-wall solenoid with a finite length, the expression of vector potential is derived by using the method of cylindrical function expansion. The expressions of magnetic field distribution in the integral form are presented by employing the relation between vector potential and magnetic induction. The expressions in the series form of the interior and exterior magnetic field distribution of magnetic field of a thick-wall solenoid are calculated by means of the integration method directly. The magnetic field at central axis is obtained by applying the formulae of this paper.

Key words: thick-wall solenoid, steady current, magnetic induction, series expression