碳纳米管磁化氢等离子体薄膜的微波吸收特性

Microwave absorbing properties of the film of magnetized hydrogen plasma in carbon nanotubes

为从理论上掌握有外加静磁场存在时铁催化高压歧化生成的碳纳米管中氢等离子体的微波吸收特性,根据磁离子理论和Appleton-Hartee方程,采用W.K.B近似方法,导出了碳纳米管磁化氢等离子体薄膜的微波衰减系数公式,数值计算了不同条件下碳纳米管磁化氢等离子体薄膜在0.3～30 GHz频段的微波衰减系数。研究结果表明:随着外加磁场强度的增加,Att>30.00 dB/cm的频宽明显增大,吸收峰向高频方向移动.适当控制碳纳米管中等离子体的自由电子密度、电子碰撞的有效频率和外加磁场强度,能够实现碳纳米管中磁化氢等离子体薄膜对对特定微波段的强吸收.在外磁场等于0时,运用所构建的微波吸收模型得到的数值计算结果与已有的实验数据相吻合.

To clarify the microwave absorbing properties of the hydrogen plasma in iron-catalyzed high-pressure disproportionation-grown carbon nanotubes （CNTs） in the uniform magnetic field, the microwave attenuation coefficient of the film of magnetized hydrogen plasma in CNTs was deduced based on magneto-ionic theory, Ap- pleton-Hartree Equation and W. K. B approximation. The microwave attenuation coefficient of the film in the range of 0.3 - 30 GHz under different conditions were calculated. The results indicate that when the external magnetic field strength increases, the frequency bandwidth of maximum absorption attenuation exceeding 30.00 dB/em increases obviously, and the absorption peak moves from low to high frequencies. It is proposed that as long as external magnetic field strength, liberal electron density and electronic effective collision fre- quency in plasma in CNTs are modestly controlled, strong microwave absorption, for specified frequency range, can be obtained. When the external magnetic field is turned off,the numerical results of the microwave attenua- tion coefficient of the film are in good agreement with the experimental data.