博文
轫致辐射
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原指高速电子骤然减速产生的辐射，如X光管中高速电子轰击金属靶骤然减速，产生高能X射线束；后泛指带电粒子碰撞过程中发出的辐射。当带电粒子的速度v<<c时，轫致辐射与电离相比显得并不重要，其方向性不强；当带电粒子的速度接近光速时，轫致辐射是其能量损失的主要机制，轫致辐射引起的角分布向前倾，随着速度增大，向前倾的程度增大。轫致辐射的重要特征是具有连续谱，其强度在很宽的频谱范围内缓慢变化。除了X射线管中产生的X射线连续谱属于轫致辐射之外，轫致辐射在热核聚变反应中也是重要的 ，在β衰变过程中电荷的突然产生或电荷的突然消失（如电子俘获）也伴随有轫致辐射。天文观测中轫致辐射也是常见的现象，如在中子星表面因热轫致辐射引起的X射线辐射。
逆轫致辐射 inverse bremsstrahlung
补充：
等离子体中的轫致辐射主要来自电子与离子的远碰撞，它是一种连续辐射,波长分布在紫外线到X射线范围内。对于高温（几百万摄氏度以上）等离子体来说，轫致辐射是一种重要的辐射。
回旋辐射是磁场中的等离子体带电粒子绕磁场作回旋运动时产生的辐射。电子的辐射比离子的强。辐射的频率是电子的回旋频率和谐频。回旋辐射是磁场中高温等离子体的重要的辐射。
对于弱电离的低温等离子体，轫致辐射和回旋辐射可以忽略，而线辐射和俘获辐射则占主要地位。线辐射是分子、原子和电子在跃迁过程中的辐射。俘获辐射是自由电子与离子近碰撞时被离子俘获形成一个新的离子或中性粒子时的辐射，它是连续辐射。
补充：
"Bremsstrahlung" means "braking radiation" and is retained from the original German to describe the radiation which is emitted when electrons are decelerated or "braked" when they are fired at a metal target. Accelerated charges give off electromagnetic radiation, and when the energy of the bombarding electrons is high enough, that radiation is in the x-ray region of the electromagnetic spectrum. It is characterized by a continuous distribution of radiation which becomes more intense and shifts toward higher frequencies when the energy of the bombarding electrons is increased. The curves above are from the 1918 data of Ulrey, who bombarded tungsten targets with electrons of four different energies.
The bombarding electrons can also eject electrons from the inner shells of the atoms of the metal target, and the quick filling of those vacancies by electrons dropping down from higher levels gives rise to sharply defined characteristic x-rays.
source：http://hyperphysics.phy-astr.gsu.edu/Hbase/quantum/xrayc.html#c2
图：
Spectrum of a wedding ring (yellow: background bremsstrahlung, computed)
https://m.sciencenet.cn/blog-111973-50696.html
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