About collision block

[TrumeAAA]

Hi, I have a question about the collision block. I the documentation, it says that if the "use_collisions" flag is omitted, there won't be collision in the simulation. I am confused that: when there isn't "collision block" at all, will collisions be included? since in this case the flag is also "omitted". Ai.

[Status-Mirror]

Hi @TrumeAAA,

By default, no collisions are performed. There are two reasons you might want to include a collisions block, but still switch off collisions:

• If you want to run many simulations where you switch collisions on an off, without having to modify the input.deck much
• If you want to run the code with collisional-ionisation, but not Coulomb scatter between charged particles

Hope this helps, Stuart

[TrumeAAA]

Hi, I understand what you said. It helps a lot! Thank you very much! Ai.