疏松型螺线管电流轴线上磁场的数值计算

应用数值模拟方法，细致地分析了疏松型螺线管电流轴线上的磁场随螺距和轴线上位置的变化关系，计算结果表明，当螺距较大时，其磁场分布与密绕螺线管电流的磁场分布相差很大，磁场沿轴线和垂直于轴线的方向都有分量，螺距越大，垂直于轴线方向的磁场分量越大；但当螺距较小或距螺线管中心较近外，磁场几乎与密切螺线管电流产生的磁场相当，可用表述密绕螺线管电流的轴线上磁场的简单公式来近似。

Numerical calculation of magnetic field distribution along axis of a helical current

In order to analyse the magnetic field distribution of sparse spiral tube current along its axis completely, numerical simulation is undertaken. The result shows that there is a much different between sparse spiral tube and close spiral tube current when the pitch is relatively large. But when the pitch is relatively small or at the farther position away from the helical coil center, the magnetic field has a similar distribution as the close spiral tube coil.