When two concentric circular wires carrying currents in the same direction are considered, the inner wire experiences a magnetic force due to the magnetic field produced by the outer wire.
How to get the force on the inner wire
According to Ampère's law, a current-carrying wire generates a magnetic field around it. When a second wire carrying current is placed within this magnetic field, it experiences a force due to the interaction between the magnetic fields produced by both wires.
For wires carrying currents in the same direction, the magnetic field produced by the outer wire will create magnetic field lines that intersect the inner wire.