Discussion Forum

Hi, the townsend coefficients are generated by the Boltzman Solver. You insert the Cross Section Data in the Boltzman Solver and then you can compute the townsend coefficients. The main problem is that when you download the cross section data from lxcat you must add the statistical weights to the data sets, because comsol need them.

Hi, the townsend coefficients are generated by the Boltzman Solver. You insert the Cross Section Data in the Boltzman Solver and then you can compute the townsend coefficients. The main problem is that when you download the cross section data from lxcat you must add the statistical weights to the data sets, because comsol need them.

Hi Phil, thanks for your reply. You mean if I load the cross section of N2 and O2 and the ratio of these two/or more species, comsol will generate the townsend coefficients of the mixture instead of that of each species. Also, do you know how statistical weight is calculated? I attached what I found in the book but it seems to be different from the data listed in the cross section of the Comsol example of the O2 Boltzman. I attached data of the rotational excitation comsol used. One more question, do you know how the third number of the third line is determined? It's a flag that determines whether or not a detailed balance is used. What do they mean by detainled balance? Thanks so much!

the boltzman solver generates the townsend coefficients for each reaction you add to the solver. For the first reaction you recieve for example alpha1. For the second reaction you recieve alpha2. Unfortunately I dont know how to calculate the statistical weights or how to get them. Comsol uses the cross section data from lxcat and there are no weights, maybe Comsol uses another cross section data. Obviously for the mixture of air you need N2 cross section data with the weights and in the tutorial corona discharge air they used such a cross section file. I do not know what they mean with the third number. I'm also interested in these questions.

so the townsend coefficient is for each reaction of each species. In the example they use the townsend of specie A which represents the mixture of 4:1 nitrogen and oxygen.