Inside a so called "Helmholtz cage" you can try to reproduce the wanted magnetic field environment necessary for your simulation (see the pdf in the link I have attached).
You will also need to simulate the Earth magnetic field on a particular orbit to generate the required values for the Helmholtz cage controlers. You can do that by propagating orbit of the satellite and calculating IGRF geomagnetic model at each satellite location. I can share Scilab/CelestLab scripts. If you need it please contact me privately.
Here is a cheap solution, https://www.amazon.com/dp/B005LY4TCU/_encoding=UTF8?coliid=I1B2CBGO6MDQJW&colid=13MJAZ5GGDSM5 used by many cubesat teams, however you need to calculate the EMF strength at the target orbit altitude, here are some videos on how it works: