A Faraday cage is a structure made of conductive material, such as metal, that is designed to block or redirect electromagnetic fields. It works by creating a shield that absorbs and redistributes electromagnetic radiation, thereby preventing it from passing through to the interior of the cage. However, a Faraday cage is not designed to block static magnetic fields, such as the Earth's magnetic field.
The Earth's magnetic field is primarily a static magnetic field, which means it has a constant direction and magnitude in a given location. Unlike electromagnetic radiation, which consists of oscillating electric and magnetic fields, static magnetic fields do not generate changing electric fields that can be absorbed and redirected by a Faraday cage.
To block or shield a static magnetic field like the Earth's magnetic field, a different approach is required. One method is to use specialized magnetic shielding materials, typically made of highly permeable alloys, that can redirect the magnetic field lines away from the protected area. These materials, often referred to as mu-metal or permalloy, provide a path of lower resistance for the magnetic field, effectively diverting it around the shielded space.
It's important to note that complete blocking of the Earth's magnetic field is not practically feasible because the field is pervasive and extends throughout the entire planet. However, magnetic shielding materials can significantly reduce the strength of the field in a localized region, providing some level of protection or isolation from its effects.