Magnetic field around a solenoid
If we now add another loop with the current in the same direction, then the magnetic field around each loop can be added together to create a stronger magnetic field. A coil of many such loops is called a solenoid. A solenoid is a cylindrical coil of wire acting as a magnet when an electric current flows through the wire. The magnetic field pattern around a solenoid is similar to the magnetic field pattern around the bar magnet that you studied in a previous lesson, which had a definite north and south pole as shown in the figure below.