Question

What is the shape inside of a current carrying conductor whose magnetic field pattern resembles that of a bar magnet?

Answer 1

Magnetic Field Generated by Current: (a) Compasses placed near a long straight current-carrying wire indicate that field lines form circular loops centered on the wire. (b) Right hand rule 2 states that, if the right hand thumb points in the direction of the current, the fingers curl in the direction of the field.

Answer 2

A coil with a metallic core, aka a solenoid. Because of the shape the fields of the coils are 'pointing' in the same direction. The field strength depends on the current through the wire/coil, the diameter of the coil and the diameter of the coil and the magnetic behavior of the core.