Question: is radha and rukmini the same?
Answer: As Anupama Kurup mentions, some qualities are similar-but that is precisely because they come from the same source (but are not the same as Radha). Specifically, Rukmini devi is considered an incarnation of the gopi-Candravali and/or Lakshmidevi. Radha's name is mentioned in Bhagavatam many times, but indirectly.