Power of Augmentation Ideals of Group Ring Let $R[G]$ be a group ring and $w$ be an augmentation ideal of $R[G]$. What is meant by the power of augmentation ideal of $R[G]$, $w^n$? I couldn't find a formal definition in any literature. Is it just simply mean that $w^n=\\{g^n|g\in w\\}$?

It should just be the same as the definition of the power of any ideal, that is:

$I^n=\left \\{\sum_{k=1}^m\prod_{j=1}^n i_{jk} \mid i_{jk}\in I, m \in \mathbb N\right\\}$