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How do I model space charge by charged particles

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Joohwa Lee

Joohwa Lee

September 2, 2010 10:58am UTC

How do I model space charge by charged particles

Hello!

I am trying to simulate trajectories of charged particles under electric field.
As charged particles travel in the space, they leave space charge density.
This space charge density alters electric field (or potential) and therefore the motion of charged particles is affected.

I can compute electric field (or potential) by solving Poisson's equation.
The trajectories can be obtained in Particle Tracing at Postprocessor.
However, these trajectories do not make space charge...
How can I feedback the space charge into Poisson's equation and do particle tracing?

Thanks,

Starry

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Per Sundqvist

Per Sundqvist

September 3, 2010 2:01pm UTC in response to Joohwa Lee

Re: How do I model space charge by charged particles

Its a diffusion equation you have to add.

rho=e*n in Poisson

and diffusion

dn/dt=div(kB*T*grad(n)-e*grad(V)*n)/mu

Un fortunately it can be overdamped so convergence gets bad... (kB*T*grad(n)<<<<e*grad(V)*n)

Otherwise it is a MonteCarlo simulation you need and take rho=sum of all particles...

Best,
Per

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