Previously, oscillations between low and high density plasma was reported at JET. In present work we have attempted to develop this further based on the new discovery of Dielectronic Recombination (DR) in singly ionized carbon, C II, at the divertor of the JET tokamak. It is observed at the CFC outer target plate by a direct imaging spectroscopic system covering the far UV up to IR with a wavelength resolution of less than 1 Å. Unlike the direct electron capture processes Radiative Recombination (RR) and Three Body Recombination (TBR), DR is an indirect resonant electron capture process with two electrons simultaneously participating and therefore not allowed for hydrogen, deuterium, tritium and hydrogen-like ions. In the DR process studied in the present work, a free electron is captured by the ground state 1s22s2 1S0 of C III, the lowest ionization limit of C II, with a simultaneous inner-shell 2s-2p excitation forming doubly excited doublet and quartet states of C II of the 1s22s2p(3P)nl 2,4L terms. characters. If a state of this kind is lying above 1s22s2 1S0 it might be subject to auto-ionization due to spin-orbit configuration interaction between the LS-allowed doublet and LS-forbidden auto-ionizing quartet states in C II. Although the interaction may be weak, in the order of 10-1 ­ 10-2 percent, the high auto-ionization rate (Aa) in the order of 1013 ­ 014 s-1 is sufficient for inducing appreciable auto-ionization into quartet states. In present work we have focused on the metastable and the highly auto-ionizing 1s22s2p(3P)4s 4P and 1s22s2p(3P)3d 2F resonant states of C II by analyses of the 2s2p(3P)3p 4D - 1s22s2p(3P)4s 4P and 2s2p(3P)3p 2D - 1s22s2p(3P)3d 2F transitions lying at 3581-3590 Å and at 7996-8000 Å, respectively, schematically shown in figure 1. The resonant states of the 4s 4P and 3d 2F terms are lying 1.60 and 0.41eV above the 1s22s2 1S0 ground state of C III, respectively. The level structure of the 2s2p(3P)3p 4D ­ 2s2p(3P)4s 4P multiplet in Fig.2a is typical at lower electron density (ne) whereas the one for the same multiplet in Fig.2b is typical for higher ne. Further details, which are central, on this matter will be specified further on in the paper.