Discussion Forum

Hi

I'm not by my COMSOL WS so I cannot look at your models, but you have noticed, that when you add a second physics of the same type as a previous one, COMSOL renames the dependent variables, hence a E, E1 E2 ... this means that when you copy a formula from the model1 with E as dependent variable into another model (or the same model but a duplicate of the same physics) with a ariable name E1 youmust change all "E" into E1.

Another way I prefer, is to fully restart a new model (you can have 2 COMSOl running simulatneously, and copy from one to the other, then you get tha same E = E ;)

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Good luck
Ivar

The coaxial port can only cause wave propagation if you solve for the in-plane vector. You need to set the "Electric field components solved for" property to "In-plane vector".

/ Dan

Thanks,

yes, I built it new..

now, I have convergence problems.. I probably need to give surfaces for e or ions to escape..

how serious are the convergence values?
what do they mean? ist 10E9 high?
reliable physics can only be at less than 10E3 ? is that the meaning of this parameter?

the calculation stucks around the time 10E-5s and needs calculation time steps of hundreds or thousand to jump to the next "physical" time.. because this convergence parameter oscillates around 10E8 and 10E9..?

does this mean that in those physical times, the results are not "real" , later the convergence is getting abruptly better down to ?1000 (or less) or it skys high to 10E23 and stops the calculation.

How do I need to understand this convergence parameter?

can we plot this convergence parameter evolution with "physical" time ?

Thank You

Lukas

Good morning,

The model was running for 4 hours, and I stopped it..

but the results up to there look good..

thank You,

any tip to make this converge faster?

Lukas

it is 9.5MB big, the model would not upload?

I put it in the Model-Exchange list.
Feel free to help me improve it.

I would really want to have this in simple 2D.. or doesn"t it make no difference in computer load?

Hi

it's easier to save and upload unsolved models (Edit clear all solution, clear all mesh, File reset model)

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Good luck
Ivar

Hello,

seeing my results after stopping the calculations, I could understand why the convergence parameter remains high and why it takes a lot of calculating time steps..
on the first physical times from 10E-8 to 10E-6 the plasma reactions are few, only around the 10E-5 something is really happening, e-density is created..
that makes sense.. so the calculation time starts to be long then.. a lot of incrementations..

problably this is the fate of this model, wait for a while, a long while..

Thanks

Lukas

Hello,

my latest models include more detailed calculation of the plasma since I checked full calculation of transport for ion and electron, as well as full conductivity matrix.

and guess what, the calculation is faster?

so my new question:

problably directed to Daniel Smith

the microwave surface wave plasmas have a strong interrelation (strong coupling in comsol language)
E-Field and e-density really play together.
Is this the reason for 10E6 to 10E8 inverse time steps on the convergence plot?

Dr. Raeuchle (former plasma scientist at IPF Stuttgart) modeled the surface wave in Comsol3.5 and explained that he was not considering each GHz oscillation of the E-field.
Those comsol3.5 microwave plasmas calculate a bit faster than the actual mw-plasma module?

How is the microwave plasma description ? does the module really cross correlate each GHz half-wave of E-Field to the e-density (plasma conductivity) ?

Isn't it better to run in 10E-4 s steps (or diffusion time scale) and have 3 or 4 interation to steady-state distribution ?

I believe I first need to study in details the user-manuals..

Thank You

Lukas