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Charge Flow in a plasma and Solving Poisson's Eq. COMSOL v3.5a

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Hello,

In general what kind of concerns are there when modeling electron and ion motion using FEM, specifically in a low temperature plasma? If anyone can provide a good reference to a paper or text that discusses in detail issues with meshing, time stepping, etc. I would really appreciate it. I want to solve basic drift-diffusion equations along with energy balance and poisson's equation. My big concern is really solving poisson's equation simultaneously with the drift-diffusion equations since both are strongly dependent on one another. Any advice?

6 Replies Last Post 25.08.2011, 02:45 GMT-4
Daniel Smith COMSOL Employee

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Posted: 1 decade ago 30.08.2010, 17:11 GMT-4
Dear David, the Plasma Module is designed to model low temperature plasmas. Poisson's equation is solved simultaneously with the drift diffusion and ion transport equations. You can find more information and tutorials here:

www.comsol.com/products/plasma/?tab=tutorials

/ Dan
Dear David, the Plasma Module is designed to model low temperature plasmas. Poisson's equation is solved simultaneously with the drift diffusion and ion transport equations. You can find more information and tutorials here: http://www.comsol.com/products/plasma/?tab=tutorials / Dan

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Posted: 1 decade ago 30.08.2010, 18:00 GMT-4
Hello Dan,

I watched the tutorial on the plasma module. I didn't see how the poisson's equation is implemented. Typically for a an argon GEC model, can comsol 3.5A generally handle solving both the poisson's equation and drift-diffusion equation even with the coupling? What typical concerns should I have with implementing such a model?

-David
Hello Dan, I watched the tutorial on the plasma module. I didn't see how the poisson's equation is implemented. Typically for a an argon GEC model, can comsol 3.5A generally handle solving both the poisson's equation and drift-diffusion equation even with the coupling? What typical concerns should I have with implementing such a model? -David

Daniel Smith COMSOL Employee

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Posted: 1 decade ago 31.08.2010, 12:01 GMT-4
Hi, in the Plasma Module Poisson's equation is implemented in the same way as in the AC/DC module except that the space charge density is automatically computed for you based on the plasma chemistry defined in the model. The strong coupling between the electrostatic field and the electron transport is easily dealt with by COMSOL since we always use fully implicit time stepping and we solve for both in a fully coupled manner (as opposed to segregated).

The book keeping and choosing how best to implement these equations in v3.5a is probably going to be very difficult. I would suggest using the plasma module since all these details are automatically taken care of by the software.

/ Dan
Hi, in the Plasma Module Poisson's equation is implemented in the same way as in the AC/DC module except that the space charge density is automatically computed for you based on the plasma chemistry defined in the model. The strong coupling between the electrostatic field and the electron transport is easily dealt with by COMSOL since we always use fully implicit time stepping and we solve for both in a fully coupled manner (as opposed to segregated). The book keeping and choosing how best to implement these equations in v3.5a is probably going to be very difficult. I would suggest using the plasma module since all these details are automatically taken care of by the software. / Dan

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Posted: 1 decade ago 31.08.2010, 19:58 GMT-4
Thank you very much for your input. Before I switch to v4.0 I will see what I can do with v3.5a.
Thank you very much for your input. Before I switch to v4.0 I will see what I can do with v3.5a.

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Posted: 1 decade ago 31.08.2010, 23:52 GMT-4

Dear David, the Plasma Module is designed to model low temperature plasmas. Poisson's equation is solved simultaneously with the drift diffusion and ion transport equations. You can find more information and tutorials here:

www.comsol.com/products/plasma/?tab=tutorials

/ Dan



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[QUOTE] Dear David, the Plasma Module is designed to model low temperature plasmas. Poisson's equation is solved simultaneously with the drift diffusion and ion transport equations. You can find more information and tutorials here: http://www.comsol.com/products/plasma/?tab=tutorials / Dan [/QUOTE] Such a very amazing link! -- http://moviesonlineworld.com

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Posted: 1 decade ago 25.08.2011, 02:45 GMT-4
sir:
Hello! I am just simulating the rf plasma discharge with the comsol software. There are some questions .for example :When i simulated there was a note :Failed to find consistent initial values.
Last time step is not converged.I wish you can give me some advice .The modle i have build is in the accessory.
Best wishes to you .
sir: Hello! I am just simulating the rf plasma discharge with the comsol software. There are some questions .for example :When i simulated there was a note :Failed to find consistent initial values. Last time step is not converged.I wish you can give me some advice .The modle i have build is in the accessory. Best wishes to you .

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