We explain what a magnetic field is, its origin and the types that exist. In addition, intensity, direction and earth’s magnetic field.
What is a magnetic field?
The mathematical representation of the way in which magnetic forces are distributed in the space surrounding a magnetic source is understood as a magnetic fields . In other words, a magnetic fields is a field of forces that is always surrounded by a source of magnetic energy, and it is in this region where elements sensitive to magnetism interact with it , such as ferromagnetic metals . That is, that outside of this magnetic fields the effects of magnetism do not occur.
The magnetic fields are dipolar, they have a North pole and a South pole , which are also called positive pole and negative pole. And for their study, these fields are described in a vectorial way, which means that they are understood as a set of forces endowed with direction and magnitude, which can be represented by vectors in a grid.
Whenever there is a source of magnetic energy, there will be a magnetic fields around it, which describes how these magnetic forces act . The mode of interaction between magnetic fields in electrical devices, such as transformers or electromagnets, is a subject of study for the science of magnetic circuits, and has useful implications for the management of electricity.
Origin of a magnetic fields
For there is a magnetic fields source magnetic energy must also exist , such as a magnet or electromagnet, or also an electrical current in displacement . There is a correlation between electricity and magnetism, as described by the Law of Ampère and Maxwell’s equations, so magnetic fields and electric fields usually correspond. The presence of magnetic fields can be checked using an apparatus known as a magnetometer.
Types of magnetic field
Magnetic fields can be classified according to their source of creation, as follows:
- Magnetic fields from a magnet. They are those that are created naturally by a magnet or magnetized metal, and that are a consequence of the movement of electrons around the atomic nucleus of said element and also on its own axis, in a spin known in physics as spin.
- Magnetic fields from current. They are those generated by the displacement of the charges of an electric current, as in the case of electromagnets, in which an electric charge is circulated through a metallic material, thus achieving that it will imitate immediately and generate a field around it. These fields can also occur around high- voltage electrical devices , such as transformers.
Intensity of a magnetic field
The intensity of the magnetic fields is a property that refers to two different forms of magnitude of the magnetic forces that act within it, and that are:
- Magnetic excitation or field H. Understanding magnetism very similar to electricity, describes how intense the energy of the magnetic fields is in a specific and specific region of it. That is, it is determined according to the relationship of the field with its electrical sources.
- Magnetic induction or field B. Considered by physicists as the authentic measurement of the strength of the magnetic field, it is determined by the amount of magnetic flux per unit area that occurs in a given region of the field. That is, it is determined based on the effects that the field produces on its loads.
Direction of a magnetic field
The direction of a magnetic field is described using lines of force or vectors , which are lines in charge of indicating the direction where the magnetic forces converge, or where they push a load that is subject to the magnetic field.
In this sense, the variables of magnetic excitation (H) or magnetic induction (B) of the intensity of a magnetic field are vectorial, since their values change according to the proximity of the region of the studied field , with respect to the magnetic source or pole. In fewer words: the closer you are to the magnetic source, the more intense the effect will be and the more its direction will be determined.
Earth’s magnetic field
Our planet has a natural and huge magnetic field , which is called the magnetosphere or geomagnetic field. It is a consequence of the constant movement of the ferromagnetic metals that compose it, such as iron and copper , mostly as a consequence of the terrestrial rotation .
This field plays very important roles in maintaining the world’s electrical balance , diverting the impact of radiation from the sun (the so-called solar wind) as well as rejecting other forms of electromagnetism from space, which could be harmful to life (such as cosmics rays).
To this enormous field react the compasses that we use for navigation , always indicating the north, and also the specialized senses of many migratory animals, which have thanks to it an innate sense of orientation that always takes them to the same region during specific periods of their lives.