EFFICIENT IMPURITY EXTRACTION WITH MODERATE POWER OFF-AXIS ICRF HEATING IN A RIPPLED TOKAMAK

摘要

It is shown that when the resonant vertical chord ω =ω_BI (here ω is the applied frequency and ω_cI is the impurity cyclotron frequency) is located in the ripple well domain, strong convective outflux of the resonant impurity arises due to adiabatic trapping into the local magnetic well. This outflux could readily overcome the convective influx caused by parallel friction forces, thus preventing central impurity accumulation.