FFELT: how to recover the field?

[Jeroen Demeyer <jdemeyer@cage.ugent.be>]

Hello list,

Given a FFELT x in characteristic p, I would like to compute a p-th root 
of x.  The most obvious way to do this is to compute x^(p^(n-1)), where 
p^n is the cardinality of the field.  However, how can I recover p and n 
given only the FFELT?  Obviously, it suffices to get the polynomial 
defining the finite field (i.e. the argument given to ffgen()).  I tried 
x.mod, but that doesn't work.

Cheers,
Jeroen.