Discussion Forum

Hi all,

currently I am trying to simulate a plasma with the plasma module with DC Discharge, so using the drift diffusion with heavy particles. I am trying to model a plasma inside a cylinder with as steady flow of neutral gas in 2D axialsymmetric. The neutral gas flow was calculated in an other simulation before. The reaction inside the cylinder are as follows: T -> T + e- (ionization, integrated reaction rate = 2.5640E12 1/s) T -> T- (dissociative attachement, integrated reaction rate = 2.6555E10 1/s) T+ +e- -> T (recombination, integrated reaction rate = 1.4991E12 1/s) T+ + T- -> 2T (recombination, integrated reaction rate = 4.1114E9 1/s) and there are some surface reactions: T+ -> T (surface, , integrated reaction rate = 7.1052E11 1/s) T- -> T (surface, integrated reaction rate = 5.9608E10 1/s)

T+ net creation: 3.5027E11 1/s T- net creation: -3.7164E10 1/s

Electrons are eliminatey by using a non reflecting wall. The only way ions are eliminated from the system is via recombination or through surface reactions. And here is my problem: I simulated long enough, so the density of the particles doesn't change any longer. But when I sum up all creation and anihilation processes for each of the ions (T+ , T-) by using the derived values and integrating over the whole simulation area the numbers don't add up to zero as they should for a non changing system.

Sadly the 5mb limit does not allow me to upload my whole comsol file but I will attach a file with no imput for the neutral flux and hence no results. The integration setting at the derived values node was set to volume/surface integration.

I would appreciaty any help and thank you in advance.

Cheers Jonas