Plasma boundary reconstruction from reflectometer arrays

A poloidal array of reflectometers can measure local density profiles near the plasma edge. The use of this constant density surface near the plasma boundary to reconstruct the magnetic geometry is examined. This approach for plasma boundary reconstruction is most useful for fully formed plasmas where the density gradients are near to, and perpendicular to, the reflectometer antennas. For ITER this plasma boundary information would supplement the magnetic reconstruction and can be used to correct the drifts in the steady state phase. The number and location of reflectometers is analysed to determine the accuracy of the plasma reconstruction and the need for additional information.