Device for obtaining uniform axial magnetic field

The utility model provides a device for obtaining a uniform axial magnetic field, which comprises a coil barrel and a coil, and the coil is spirally wound and fixed in a thread groove on the outer wall of the coil barrel. The coil comprises a first spiral section, a second spiral section and a third spiral section which are sequentially connected in the axial direction of the coil, the turn number density of the first spiral section is consistent with that of the third spiral section, the turn number density of the second spiral section is smaller than that of the first spiral section, and the axial length of the first spiral section is consistent with that of the third spiral section. The axial length of the second spiral section is greater than that of the first spiral section; the first winding radius is equal to the third winding radius, and the second winding radius is equal to or smaller than the first winding radius. According to the utility model, the uniform axial magnetic field is obtained by contro