Help required in Electric field (AC/DC Module) simulation

I am an absolute beginner in COMSOL and need all the help I can for my project which I am doing in COMSOL. I have tried a lot to solve it on my own, but failing to do so I really hope the COMSOL community can help me out.

I have a particular structure/geometry which has to be simulated for the current density in the structure. A particular electric field/voltage is applied across the structure and the corresponding current density has to be simulated.

I need to use the Poole Frenckel equation to model the current density:

The equation is as J=uNq*E*(......)

where:

J is the current density

E is the applied electric field

The E has different values within a range, and corresponding to any value of E, I need the current density J to be simulated across the structure/device.

I request anyone to kindly guide me through this problem. If anyone need any more details to help me out, I will provide all the details.

Thank you.