I have found this topics in Nuclear physics book written by R.R. Roy and B.P. Nigam.
They are not the same thing, but in nuclear physics they are related in the following way:
You use the mathemtical technique of multiploe expansion to find out what the electromagnetic field of your nucleus looks like, which, I guess, is what you mean by multipole fields although I have not heard that term before.
You then use those properties you have found to compute specific aspects of the electromagnetic radiation that is emitted/absorbed by the nucleus or between states of the nucleus. This radiation is called multipole radiation and it is a very deep, interesting and complex field.