Edge biasing in tokamaks

An overview is presented of recent results on the creation of electric fields in the edge of limiter or divertor tokamaks. The practical implementation and theoretical basis of several schemes, generating radial and/or poloidal fields, are outlined. The manipulation of edge and scrape-off-layer profiles and the control of particle exhaust is discussed. Contributions of biasing experiments to H-mode physics are highlighted. Some prospects for biasing in next generation tokamaks are finally given.