柱形等离子体辐射场和阻抗的数值计算

由柱形非磁化等离子体色散关系，得到信号沿柱形等离子体传输波矢空间分布，再根据天线方程推导得到柱形等离子体在轴向密度均匀、不均匀情况下辐射方向图、辐射阻抗与增益等参数.理论计算结果与实验都证明了柱形等离子体辐射方向图随等离子体参数变化而改变，同时实验结果表明，重新得到的数值计算结果更加精确，更加符合实际测量结果，这对等离子体作为天线传输具有重要的参考价值. 关键词： 柱形等离子体 辐射阻抗 辐射方向图

Numerical calculation of radiation pattern and impedance of column plasma

When the frequency of the incident electromagnetic wave is lower than that of the plasma, the high-density and low-temperature plasma column is equivalent to a good conductor. However, because of the dispersive relation and the uneven distribution of density, the wave vector propagating along the plasmas is not a real constant, but a complex quantity varying with the change in the space. So, it is hard to calculate the radiation pattern, radiation impedance and gain of the column plasma with the normal methods used with the metallic antenna. In this paper, the space distribution of the wave vectors of the signal along the column plasma is calculated from the dispersive relation of the non-magnetized columnar plasma. And then, according to the antenna equation, the radiation pattern, radiation impedance and gain of the columnar plasma with even or uneven axial density distribution can be derived. The experimental results show that the numerical values calculated by this new method are much more accurate. This method will be of great importance in the application of the plasmas in the antenna transportation.