  We construct the Z_k parafermions as diagonal affine cosets and apply them to
the quantum Hall effect. This realization is particularly convenient for the
analysis of the Z_k pairing rules, the modular S-matrices, the W_k symmetry and
quantum group symmetry. The results are used for the computation of the
mesoscopic chiral persistent currents in presence of Aharonov-Bohm flux.
