Toroidal Multipolar Expansion for Fast L-Mode Plasma Boundary Reconstruction in EAST

A new method for plasma boundary reconstruction, based on the toroidal multipolar expansion (TME) scheme, is applied successfully in EAST. TME applies a limited number of toroidal multipolar moments based on toroidal coordinates to treat a two-dimensional problem of axisymmetric plasma equilibrium. The plasma boundary reconstructed by TME is consistent with the results by using EFIT. The method is su±ciently reliable and fast for real time shape control.