连续辐射谱法计算闪电通道电子温度

摘要

Based on the continuous radiation theory,the relation between the energy of the continuous radiation and the electron temperature of the plasma is obtained.According to the spectrum of the lightning return stroke processes in Qinghai area,sepa-rating the continuous radiation intensity from it.In order to reduce the calculation error caused by absorption,the absorption characteristics are analyzed.The electron temperature of lightning discharge channel is obtained by fitting the curves of the con-tinuous spectrum intensity.The peak temperature is 29 800 K and the temperature lower limit is 16 200 K.The electron temper-ature is calculated respectively with the O Ⅰ line and NⅡ line in the same band spectrum.The comparison shows the electron temperature calculated by the continuous radiation transits from high temperature to low temperature.High temperature values are in good agreement with the temperature of the lightning core current channel calculated by the ion line information,while the low temperature is close to the result of the atomic line calculation,which reflects the temperature of the outer corona discharge channel.Therefore,the results obtained from the continuous spectrum can more fully reflect the distribution of the temperature along the radial direction.For the lightning thermal plasma channel,the continuous spectrum method provides a new way to cal-culate the electron temperature of lightning discharge channel.It is of great significance to the study of the lightning return stroke.%基于连续辐射理论,得到连续辐射能量与等离子体电子温度的关系式.依据青海地区一次强地闪回击过程的光谱,从中分离出连续辐射强度,对其吸收特征进行分析以减小吸收带来的计算误差.通过对连续谱强度的曲线拟合得到闪电放电通道电子温度,温度峰值为29800 K,温度下限为16200 K,由同一波段光谱中的O Ⅰ线和N Ⅱ线分别拟合了电子温度.比较结果发现:由连续辐射得到的闪电通道电子温度从高温向低温过渡,高温值与离子线信息获得的闪电核心电流通道处的温度符合较好,而低温则与原子线计算的结果接近,反映了外围电晕发光通道的温度.所以,依据连续谱得到的结果能更全面地反映温度沿通道径向的分布.对于闪电热等离子体通道,连续谱法提供了一种计算闪电放电通道电子温度的新途径,对地闪回击研究有一定的意义.