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Ifradiation source(plasma, neutral gas cloud, etc.) in thermodynamic equilibrium orLocal thermodynamic balanceState, that is, the energy distribution of particles (molecules, atoms, ions, electrons, etc.) in the system can be expressed by Boltzmann distribution law at a certain temperature, and its radiation is called thermal radiation;On the contrary, if the particle in the radiation source is far away from the thermodynamic equilibrium distribution, its radiation is called non thermal radiation.
Chinese name
Nonthermal radiation
Field
Physics
Many new celestial bodies discovered in recent years, such asa quasar、neutron star、Interstellar moleculeRadio source, X-ray source, gamma ray source, etc., their radiation spectrum shape, polarization state, light variable characteristics, etc. are obviously different from thermal radiation. Therefore,Non thermal radiation mechanismMore and more attention has been paid to the research of.For example, quasars andRadio galaxyTherefore, it is generally believed that the power law radio spectrum with polarization characteristics can be emitted by relativistic electrons far away from thermodynamic equilibrium in the external magnetic fieldSynchrotron radiationCaused by.Another example is the strong molecular radio spectrum, which is generally believed to come fromcelestial maser Magnification.The conditions for realizing this radiation mechanism are“Particle number inversion”The energy level distribution of molecules is required to be far away from the equilibrium distribution, that is, the number of molecules at the high energy level is more than that at the low energy level.For type II and type III radio bursts of the sun (seeSolar radio burst）, when relativistic electrons can travel through the plasmaCherenkov radiationexplain.Caused by this effectPlasma waveWill be partially converted into radio radiation.As for relativistic electronInverse Compton scatteringIs an important way to generate gamma raysNon thermal radiation mechanism。
