Inquiry about plane wave simulation

[Saya]

Hello,
I'm going to do some simulations with plane wave, First I did the tutorial "3.3.4 Heating from a Standard Active Implantable Medical Device" and I have some questions.
-Where is the origin (source) of the field?
-When I try to get the 0.1 g PsSAR value using "Dosimetry" in the ribbon, I the following error appears "unable to compute constant mass cubes, internal error in averaging SAR. Grid is too coarse. Please refine input grid resolution" . I checked it with a fine resolution, but it still shows this error. How I can fix this problem?

• Why the convergence does not exist in the task manager? How I can check the convergence of the simulation?
• And why the air is considered as Gel in the material?

thanks.

[Sylvain]

• the convergence is computed from the sensors. When you add an edge-source, it automatically creates a line sensor. For a plane-wave source, however, no sensors are automatically created. You can add some sensors (e.g. point sensors or current sensors) if you want to have some measure of convergence.

• the "background" is modeled as a Gel, because the simulation is for an implant in the human body and a liquid is a better approximation of the surrounding tissues than the air. Maybe the material was incorrectly called "air", but that does not play any role in the simulation (only the material properties do).

[Saya]

Thanks for your explanation. And it would be great if you would explain why PsSAR (for example 0.1 g PsSAR) could not be calculated in the plane wave simulation?
Thanks.

[Sylvain]

I can't say for sure, but it's possible your grid is still too coarse. You need to compare the size of the grid cells with the size of a cube that has a mass of 0.1g.

[Saya]

I checked it with a very fine gridding (max step = 0.1 and 0.05 for wire and insulation) as well. But I still get this error.

[Sylvain]

You need to compare the size of the grid cells with the size of a cube that has a mass of 0.1g - or provide more information, like a screenshot etc...

[Saya]

The 10 g PsSAR can not be calculated as well. The density of Gel in the simulation is 1000 kg/m^3, the length of a cube with 10 g should be about 20 mm. what the max step value should be based on the cube length? I did the simulation with the max step 0.1 mm and it seems it should be able to calculate 10 g PsSSAR. But it still can not calculate it and gives the error.