The magnetic field around a current-carrying wire can be increased by several factors:
Increasing the current: The magnetic field produced by a current-carrying wire is directly proportional to the magnitude of the current flowing through it. Increasing the current will result in a stronger magnetic field.
Coiling the wire: If the wire is formed into a coil or a solenoid, the magnetic field strength increases. The magnetic field lines generated by each loop of the coil add up, creating a stronger overall magnetic field.
Increasing the number of turns in the coil: Adding more turns to the coil increases the number of magnetic field lines and strengthens the magnetic field.
Using a ferromagnetic core: Placing a ferromagnetic material (such as iron) inside the coil or around the wire enhances the magnetic field. The ferromagnetic core concentrates the magnetic field lines and amplifies the overall magnetic field.
It's important to note that the magnetic field strength decreases with distance from the wire according to the inverse square law. Therefore, the field is strongest close to the wire and decreases as you move farther away.