Impact of PF and TF coil misalignment on toroidally asymmetric plasma error fields in TPX

Error fields from misalignment of the toroidal field (TF) and poloidal field (PF) coils in TPX are presented in terms of the outward normal B-field (B/sub /spl perp//), expanded in poloidal and toroidal harmonics (m, n), on a simulated, D-shaped, plasma flux surface. Results are reported for n=1 toroidal mode number and low poloidal mode numbers, m, and for various displacements of the TF and PF coils. In particular, results are given for the m,n=2,1 error field which interacts with the q=2 surface to cause locked modes and loss of plasma performance. Based on existing experiments, maximum permissible field errors are 4 G for the 2,1 mode and 8 G for the n=1; m=1,3,4 modes. Results are presented for a rigid shift and rotation of a single TF coil and for a rigid, radial shift of each PF coil.