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Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.

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multi-turn coil in a ICP plasma reactor

Posted 2011年12月9日 GMT-5 06:55 Low-Frequency Electromagnetics, Plasma Physics, Geometry Version 4.4 7 Replies

Gregor Primc
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Hello,

I have a problem with ICP plasma excitation. I am trying to simulate argon plasma inside a cylindrical pyrex tube (in 2D).
The excitation is done through a multi-turn coil (5 turns) wrapped around the pyrex tube.
I have drawn six small circles on the upper side of the tube and 5 small circles on the lower side. The I chose these circles in the Multi-turn coil domain in ICP module in comsol. When I simulate the problem, don't get the maximum electron density bellow the coils, but rather the density is elongated along the tube.
I am suspicious about my setting of the multi-turn coil. So can someone explain how to draw and set the multi-turn coil?

I attached the coil geometry and settings picture.

Thanks,

Best Regards,
Gregor Primc
7 Replies Last Post 2014年7月10日 GMT-4 11:11
Daniel Smith COMSOL Employee

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Posted: 1 decade ago 2011年12月9日 GMT-5 17:20
Hi, you need to use the "Coil Group Domain" feature for this type of coil. See the following examples in the Plasma Module Model Library:

Plasma Module>ICP Models>argon_gec_icp
Plasma Module>ICP Models>thermal_plasma
Hi, you need to use the "Coil Group Domain" feature for this type of coil. See the following examples in the Plasma Module Model Library: Plasma Module>ICP Models>argon_gec_icp Plasma Module>ICP Models>thermal_plasma
Gregor Primc
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Posted: 1 decade ago 2011年12月10日 GMT-5 15:23
Thank you, that did it. However, when I simulate the problem, I keep getting an error saying something about failed to evaluate variable Jacobian. I attached a picture.
I used the same variables and settings as the thermal_plasma demo case. Except my coils are round and the whole tube has the same radius and is longer.
Somewhat I don't know what this errror means...

Thanks,
Regards,

Gregor Primc
Thank you, that did it. However, when I simulate the problem, I keep getting an error saying something about failed to evaluate variable Jacobian. I attached a picture. I used the same variables and settings as the thermal_plasma demo case. Except my coils are round and the whole tube has the same radius and is longer. Somewhat I don't know what this errror means... Thanks, Regards, Gregor Primc
Gregor Primc
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Posted: 1 decade ago 2011年12月11日 GMT-5 17:45
Hello,

I managed to get rid of the error I wrote of. Now I can simulate my plasma, however I get a different kind of error.

My frequency-transient settings are:
- entry method: number of values
- start: -10
- number of values: 100
- function to apply to all values: exp10

If, at the frequnecy-transient settings, I use stop=-3.8, everything is ok and the simulation completes. If I use stop=-3.7, I get an error (see attached picture) and the simulation stops at time: 1.602543e-4.
And it doesn't mather if I choose the stop=-2. If stop is less than -3.8, I always get this solver error.

And ideas what is wrong?

Thank you,

Regards,
Gregor Primc
Hello, I managed to get rid of the error I wrote of. Now I can simulate my plasma, however I get a different kind of error. My frequency-transient settings are: - entry method: number of values - start: -10 - number of values: 100 - function to apply to all values: exp10 If, at the frequnecy-transient settings, I use stop=-3.8, everything is ok and the simulation completes. If I use stop=-3.7, I get an error (see attached picture) and the simulation stops at time: 1.602543e-4. And it doesn't mather if I choose the stop=-2. If stop is less than -3.8, I always get this solver error. And ideas what is wrong? Thank you, Regards, Gregor Primc

Attachments:

Gregor Primc
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Posted: 1 decade ago 2011年12月28日 GMT-5 09:33

Hello,

I managed to get rid of the error I wrote of. Now I can simulate my plasma, however I get a different kind of error.

My frequency-transient settings are:
- entry method: number of values
- start: -10
- number of values: 100
- function to apply to all values: exp10

If, at the frequnecy-transient settings, I use stop=-3.8, everything is ok and the simulation completes. If I use stop=-3.7, I get an error (see attached picture) and the simulation stops at time: 1.602543e-4.
And it doesn't mather if I choose the stop=-2. If stop is less than -3.8, I always get this solver error.

And ideas what is wrong?

Thank you,

Regards,
Gregor Primc


Anyone?
[QUOTE] Hello, I managed to get rid of the error I wrote of. Now I can simulate my plasma, however I get a different kind of error. My frequency-transient settings are: - entry method: number of values - start: -10 - number of values: 100 - function to apply to all values: exp10 If, at the frequnecy-transient settings, I use stop=-3.8, everything is ok and the simulation completes. If I use stop=-3.7, I get an error (see attached picture) and the simulation stops at time: 1.602543e-4. And it doesn't mather if I choose the stop=-2. If stop is less than -3.8, I always get this solver error. And ideas what is wrong? Thank you, Regards, Gregor Primc [/QUOTE] Anyone?
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 2011年12月28日 GMT-5 12:10
Hi

are you sure you do not have any number under/overflow issues with such a large time scale factor ?
And have you checked the scaling that COMSOL uses ?
there is more info if you turn on "extended log", in the solver node

--
Good luck
Ivar
Hi are you sure you do not have any number under/overflow issues with such a large time scale factor ? And have you checked the scaling that COMSOL uses ? there is more info if you turn on "extended log", in the solver node -- Good luck Ivar
Daniel Smith COMSOL Employee

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Posted: 1 decade ago 2011年12月28日 GMT-5 13:00
Hi, it's possible that the plasma is simply "going out". This means that the electron density or any of the plasma species number densities goes to zero. Since COMSOL solves for the equations in log() form, the solver encounters log(0) and the solver throws an error. The same is true for the electron temperature. You can plot them and see if the value of any of them approach zero. If you still have issues then send your model to support and we can look at it.
Hi, it's possible that the plasma is simply "going out". This means that the electron density or any of the plasma species number densities goes to zero. Since COMSOL solves for the equations in log() form, the solver encounters log(0) and the solver throws an error. The same is true for the electron temperature. You can plot them and see if the value of any of them approach zero. If you still have issues then send your model to support and we can look at it.
Matthew James
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Posted: 1 decade ago 2014年7月10日 GMT-4 11:11
Hi Gregor,

I am also looking to do this. Would you be able to upload your model file for me to look at?

Thanks
Hi Gregor, I am also looking to do this. Would you be able to upload your model file for me to look at? Thanks

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