What is known about the structure of $J_{0}(N)$ over $\mathbb{Q}[\mu_{p^{\infty}}]$?
More generally, what do we know about $J_{0}(N)$ over $\mathbb{Q}[\mu_{p^{\infty}},k^{1/p^{n}}]$, where $k\in\mathbb{Z}$?
Does it have infinite rank? Does it have finite torsion?
I am especially interested in the case where $N$ is the conductor of an elliptic curve with additive reduction at $p$. (This curve acquires, of course, a semistable Néron model over $\mathbb{Q}[\mu_{p^{\infty}}]$.)