Electromagnetic radiation (Electromagnetic waves)

Electromagnetic radiation (Electromagnetic waves) – Any movement of electric charges causes electromagnetic radiation. Depending on the conditions, it can exhibit both wave and corpuscular properties. This is a quantum of electromagnetic radiation, which is called a photon. With the help of electromagnetic radiation, it is possible to achieve the maximum propagation velocity in nature (see the speed of light). The direct range of its spectral range (see Spectrum) covers gamma rays through X-rays, ultraviolet radiation, visible light, infrared radiation, visible energy and radio waves. In the absence of cosmic rays, which have a lower speed of movement and, accordingly, have less informative value, electromagnetic radiation is for us the only source of information about distant objects in the Universe.
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Non–thermal radiation is electromagnetic radiation that occurs under nonequilibrium physical conditions when there is no thermodynamic equilibrium. It does not differ in any way from thermal (see here) or electromagnetic radiation, except for some features in its spectral composition. His behavior does not comply with the laws of Wine, Planck and Stefan-Boltzmann.
Data on three types of its generation mechanisms have been published.
Non-thermal radiation occurs as a result of the movement of relativistic particles in physical fields (see Physical fields; Synchrotron radiation). Here you can observe clusters of relativistic particles that are located near pulsars and supernova remnants.
The next mechanism that contributes to its appearance is associated with unstable and large-scale processes in plasma (see Plasma) objects or their fragments. This mechanism is the reason why non-thermal radio emission from the solar corona takes place.
In the third variant, non-thermal radiation occurs as a result of the energy of thermal motion of particles of matter, which are electrons. This phenomenon is similar to what happens when thermal radiation occurs, but there is no thermodynamic equilibrium here. This, for example, can happen if the substance manages to accumulate most of the energy before equilibrium is reached.
Heating.
Thermal electromagnetic radiation, which occurs due to the energy of thermal movement of particles of matter, mainly electrons, is called thermal radiation. At the same time, the emitting object must be in a state of thermodynamic equilibrium, which assumes a constant temperature (see Temperature) distribution throughout the entire volume of the substance being studied. Surface thermal radiation does not differ from radiation that has a different spectral composition (see Spectrum). Thermal radiation has properties described by the laws of Wien, Planck and Stefan-Boltzmann.