Discussion Forum

Hello all,

Firstly, I just would like to thank you for any help in advanced, since I am currently a bit stuck on a certain problem. I am just starting to use COMSOL in my work and so I may just be missing something simple but I am finding no easy answer to defining a constant current / current density to run through a simplified Stellarator magnet design.

The fact that this is a 3D magnet that is not symmetrical I cannot think of simple equations to use to generate a constant current density using the External Current Density feature as you could with say a circular coil. So I am wondering if there is another option than trying to deduce equations for the x,y, and z parameters of the current density of this coil to generate the appropriate current? The only real parameter to note is that the defined current for this magnet design to be running through the copper coils is -1.773333e+05 A. This simple model was generated first in Solidworks and then imported over to COMSOL for analysis of the Magnetic Flux and the magnetic stress on the coil for a start.

Another problem worth mentioning is that the coil will be made up of 45 coil packs connected together like this one with each rectangular coil of copper having a circular cut out where active water cooling will run. In attempts to mesh just one of these coil packs with an inner cylinder of water, the meshing would always give an error that says that it fails to generate the mesh for a certain domain, or says an error is due to an edge or boundary problem. I hope someone can shed some light on these issues, thanks.

The first attached model is the simplified single coil with no water cooling. ( focused on the current definition issue)
The 2nd attached model is one coil with the inside cylinder for water cooling ( focused on mesh issue )

-Joshua