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Electric & Magnetic Fields used in Particle Tracing Simulation

Niek Applied Nuclear Physics

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I am currently trying to simulate particle trajcetories through a magnetic and an electric field. I know how to couple the particle trajectory time dependent study with the electrostatic stationary study:

Charged particle tracing Physics --> Electric force --> use force from ES Multiphysics node --> Electric Particle Field Interaction --> source and destination Time dependent study --> do not solve for ES instead use variables not solved for --> Solution of stationary ES field study.

However, this is only possible for 1 stationary study. How do I also add magnetic forces that are calucluated with a secondary stationary study?

Is there a way to add another node to solve for** variables not solved for** ES + MF ?


3 Replies Last Post 26.02.2021, 03:26 GMT-5
Christopher Boucher COMSOL Employee

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Posted: 4 years ago 23.02.2021, 09:57 GMT-5
Updated: 4 years ago 23.02.2021, 09:58 GMT-5

Hi Niek,

You can see the examples "Quadrupole Mass Filter" and "Quadrupole Mass Spectrometer" which show how to define forces on the particles that are taken from two different physics interfaces and solved for in two different studies:

https://www.comsol.com/model/quadrupole-mass-spectrometer-10653 https://www.comsol.com/model/quadrupole-mass-filter-12039

The main idea is to use the first solution as the "Values of Variables not Solved For" in the second study, and then to use the second solution as the "Values of Variables not Solved For" in the third. So the first solution gets passed to the third study indirectly, through the second.

Best, Chris

Hi Niek, You can see the examples "Quadrupole Mass Filter" and "Quadrupole Mass Spectrometer" which show how to define forces on the particles that are taken from two different physics interfaces and solved for in two different studies: https://www.comsol.com/model/quadrupole-mass-spectrometer-10653 https://www.comsol.com/model/quadrupole-mass-filter-12039 The main idea is to use the first solution as the "Values of Variables not Solved For" in the second study, and then to use the second solution as the "Values of Variables not Solved For" in the third. So the first solution gets passed to the third study indirectly, through the second. Best, Chris

Niek Applied Nuclear Physics

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Posted: 4 years ago 25.02.2021, 06:02 GMT-5

https://www.comsol.com/model/quadrupole-mass-spectrometer-10653

Hi Chris,

Thank you for your reply. So I will need three studies? 1. E field solver (S) 2. B field solver (S) 3. cpt solver (TD)

I do understand what you mean, but it does not seem to work. I feel like there is something going wrong in the cpt module, connecting both MF and particle tracing.

See the attached file, sorry for the messy results section. I am trying to first solve the EFIELD_solver then the BField solver study (input from Efield solution as dep. var) and connect them in the particle_tracing study (input from BField solution as dep. var.).

>https://www.comsol.com/model/quadrupole-mass-spectrometer-10653 Hi Chris, Thank you for your reply. So I will need three studies? 1. E field solver (S) 2. B field solver (S) 3. cpt solver (TD) I do understand what you mean, but it does not seem to work. I feel like there is something going wrong in the cpt module, connecting both MF and particle tracing. See the attached file, sorry for the messy results section. I am trying to first solve the EFIELD_solver then the BField solver study (input from Efield solution as dep. var) and connect them in the particle_tracing study (input from BField solution as dep. var.).


Niek Applied Nuclear Physics

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Posted: 4 years ago 26.02.2021, 03:26 GMT-5

Update.

I managed to do it now.

Make a stationairy study that solved both the E-field and the B-field: Physics and Variables Selection --> Physics Interface--> solve for --> electrostatics (es) & Magnetic Fields (mf) Physics and Variables Selection --> Multiphysics Coupling --> solve for --> Electric & Magnetic Particle field interaction

Use this static field solution for both fields as input solution for a time dependent cpt study: Physics and Variables Selection --> Physics Interface--> solve for --> Charged Particle Tracing Physics and Variables Selection --> Multiphysics Coupling --> solve for --> Electric & Magnetic Particle field interaction Values of Dependent Variables --> Values of variables not solved for --> Settings (user controlled) --> method (solution) --> study (E&B Field, stationary)

The E&B Field stationary being the static field solution from above.

Update. I managed to do it now. **Make a stationairy study that solved both the E-field and the B-field:** Physics and Variables Selection --> Physics Interface--> solve for --> electrostatics (es) & Magnetic Fields (mf) Physics and Variables Selection --> Multiphysics Coupling --> solve for --> Electric & Magnetic Particle field interaction **Use this static field solution for both fields as input solution for a time dependent cpt study:** Physics and Variables Selection --> Physics Interface--> solve for --> Charged Particle Tracing Physics and Variables Selection --> Multiphysics Coupling --> solve for --> Electric & Magnetic Particle field interaction Values of Dependent Variables --> Values of variables not solved for --> Settings (user controlled) --> method (solution) --> study (E&B Field, stationary) The E&B Field stationary being the static field solution from above.

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