Plasma is a Layer 2 scaling approach for smart contract platforms, utilizing a network of bidirectional state channels to track state seperately from the base blockchain. Plasma can be considered a generalized form of the Lightning Network, with the former enabling channel management for all smart contracts, beyond the payment management of the latter. Plasma, like Lightning, relies on state being managed in channels on an overlay network to the base blockchain. Global consensus is maintained through challenge periods of state modified trough a state channel. The Plasma whitepaper was written by Vitalik Buterin and Joseph Poon, the author of the Lightning Network whitepaper.