How about an air-cored choke in place of the 0.5 ohm resistance?
Since you want some DC resistance anyway, magnet wire could be quite a thin gauge, and 1mH or even 20mH could be quite compact. However, if you want a high power rating, you could probably wrap the wire around a small glass jar, and immerse that inside a larger jar with oil or something like that.
Since you want some DC resistance anyway, magnet wire could be quite a thin gauge, and 1mH or even 20mH could be quite compact. However, if you want a high power rating, you could probably wrap the wire around a small glass jar, and immerse that inside a larger jar with oil or something like that.