提出一种利用无源电探针探测激光焊接光致等离子体的方法。 采用光电同步采集系统对激光焊接光致等离子体进行研究， 利用无源电探针和光纤式光谱仪探测光致等离子体， 利用等离子鞘层理论分析电信号， 并运用相对光强法计算出光致等离子体的电子温度， 比较同步光电信号分析结果。 将不涂覆表面物质以及表面分别涂覆KF和TiO2三种情况下的计算结果进行对比， 对影响结果准确性的因素进行分析。 研究结果表明通过无源探针法计算等离子体温度与光谱信号计算结果基本吻合， 准确度受等离子体离子质量的影响。 无源电探针法能够反映激光焊接光致等离子体内温度变化， 具有较好的实时性， 可以作为激光等离子体监测手段。

An approach to detecting laser-induced plasma using passive probe was brought up. The plasma of laser welding was studied by using a synchronous electric and spectral information acquisition system, the laser-induced plasma was detected by a passive electric probe and fiber spectrometer, the electrical signal was analyzed on the basis of the theory of plasma sheath, and the temperature of laser-induced plasma was calculated by using the method of relative spectral intensity. The analysis results from electrical signal and spectral one were compared. Calculation results of three kinds of surface circumstances, which were respectively coated by KF, TiO2 and without coating, were compared. The factors affecting the detection accuracy were studied. The results indicated that the results calculated by passive probe matched that by spectral signal basically, and the accuracy was affected by ions mass of the plasma. The designed passive electric probe can be used to reflect the continuous fluctuation of electron temperature of the generated plasma, and monitor the laser-induced plasma.