Plasma boundary identification in HL-2A by means of the finite current element method

In this paper, the finite current element (FCE) method used in HL-2A is described. The calculation and test results show that the error of the reconstructed boundary given by the FCE method (<3mm) is smaller than that obtained by the current filament method used before (<6mm). Even if some current elements are located out of the plasma boundary, the FCE method can also identify the plasma boundary successfully. If the location of the finite current elements is changed in a certain area, the error of the reconstructed boundary is always very small. By employing a conventional PC (Pentium 4 2.4GHz), the calculation time of one set of plasma discharge parameters does not exceed 1ms. Thus, the FCE method can identify the diverted plasma configuration quickly and accurately. This is essential and important for real-time shape control in HL-2A.