电磁波在磁化等离子体中传输机理研究

摘要

通过联立电磁波波动方程与磁化等离子体中电子的运动方程,得到了电磁波传播的色散方程,求解色散方程得到了磁化等离子体对电磁波的折射率及逆韧致吸收系数.可以得出,随着外加磁场的增强,等离子体截止波长明显变短,导致低频电磁场无法穿过等离子体.对于1μm左右波长的电磁波,等离子体的折射率和逆韧致吸收系数几乎不随外加磁场强度的变化而变化.对于10 μm左右波长的电磁波,等离子体的折射率随外加磁场强度的增强而减小,而逆韧致吸收系数随外加磁场强度的增强而增大.理论分析和数值结果阐明了电磁波在磁化等离子体中的传输机理,对研究激光复合焊接中磁场和等离子体对激光传播的影响具有指导意义.%With wave equation of electromagnetic wave and motion equation of electron in magnetized plasma,the dispersion equation of propagation of electromagnetic wave is obtained,through which the refractive index and inverse bremsstrahlung absorption coefficient of magnetized plasma are derived.It can be found that the cut-off wavelength of plasma decreases obviously as the intensity of external magnetic field increases,resulting in the low frequency electromagnetic wave cannot pass through the plasma.For electromagnetic waves with around 1 μm wavelength,the refractive index and inverse bremsstrahlung absorption coefficient of plasma barely change with the intensity of external magnetic field.For electro-magnetic waves with around 10μm wavelength,the refractive index of plasma decreases as the intensity of external magnetic field increases,while the inverse bremsstrahlung absorption coefficient of plasma increases with the rise of intensity of external magnetic field.The theoretical analysis and numerical results reveal the mechanism of electromagnetic wave propagation in magnetized plasma,which has theoretical significance in study of effect of external magnetic field and plasma on laser propagation in laser hybrid welding process.