Broadening Calculation of HeI 10830 Line in Solar Limb Flare

The Doppler broadening, Stark broadening and various kinds of broadening parameters of HeI 10830 A line in solar flare are calculated and discussed and consequently the following results are got: radiation damping can be neglected when compared with Doppler broadening, and in the case of generally accepted electron density in a solar flare (Ne= 3.2 ×1013 cm3 ), all the damping terms will not lead to distinguishable broadening in the HeI 10830 A profile. All the damping effects will not result in discernible increment of the half width of HeI 10830 A until the electron density reaches to 1015 cm3 when the largest increment is about 10-3A. Therefore. the line center of HeI 10830 A line can be taken as Doppler broadening. When electron density is greater than 1014 cm3 , Stark broadening, especially that by electron collisicn, will play a major role in the broadening of HeI 10830 A line. In order for the half width of the line resulted from Stark broadening to be 1-2 times greater than that from Doppler broadening, the half width from damping effect will be equivalent to that from Doppler effect. Consequently, the electron density will be of the order of 1017 cm3 if we interpret the observed HeI 10830 A profiles in the 1989 limb flare by Stark broadening. Broadening effect caused by collision with helium atom (γ3) has different impact on I12 and I3 component. The impact on I12 is about one order greater than that on 13. The observed HeI 10830 A profiles of 1989 limb flare show that I12 and I3 have almost the same extended profile, therefore, they can not result from γ3.