search

ECP-WarpX / WarpX

WarpX is an advanced electromagnetic & electrostatic Particle-In-Cell code.
https://ecp-warpx.github.io
Other
290 stars 184 forks source link

Non-conserved total weight of intra-species collision in DSMC module #4992

Open Zhonghai-Zhao opened 2 months ago

Zhonghai-Zhao commented 2 months ago

I found that there maybe some problems in DSMC module (24.05 version) when compute intra-species collision. The total weight and number of macro-particles decrease rapidly (within 1000 steps), as shown in the figures below. However, for inter-species collision, the total weight is well conserved. What could I do to solve this problem? total_weight total_particle

roelof-groenewald commented 2 months ago

Hi @Zhonghai-Zhao. Thanks for raising this issue. Could you please provide some more information on the details of your simulation? Perhaps providing the input script you are using?

Zhonghai-Zhao commented 2 months ago

Hi @Zhonghai-Zhao. Thanks for raising this issue. Could you please provide some more information on the details of your simulation? Perhaps providing the input script you are using?

Hi, @roelof-groenewald ! I performed the 1D simulation, and the following are the input script and cross section used. wave_1d_test.txt n-n-colision-0.25.txt

roelof-groenewald commented 2 months ago

Thanks for sharing the inputs.

I expect the problem is the following: The DSMC routine creates new particles during each collision, but when the collision occurs intra-species the number of new particles to create is not accurately calculated (essentially the new particles from the original collision pair overlaps).

In order to confirm that this is the problem, could you please do the following:

and see if you still get the decrease in neutral weight? Thanks in advance!