Find volume current distribution
A homework, I guess.

About 200 years ago it was generally accepted that static current distibution  generates a magnetic field which has vector curl equal with the current density. The most common form of that law is this:



So, present H as vector field and calculate its curl. Nabla is for rectangular coordinates, but cylindrical coordinates fit better in this case. Find the curl presented in cylindrical coordinates at first.

BTW. This isn't actually as elementary mechanical substitution case as it at first seems to be. If Ho isn't zero you need infinite current density (=a certain current packed to zero thickness area) plus a continuously distributed current.