Light for donut shape object.

I have a donut shape object, and I want to use it as light. I have set the material as shader/ self-illumin/diffuse. I also added lights component. Here is the problem, it doesn't illuminate as if it was light, it's just a white donut shape. I tried to add lights or halo, but it position the light and halo in the middle of the object, where it is empty.

Any ways to make the donut shape object itself glow?

Thanks!