Variations of the gas physical conditions along the jet and in the low- (LVC, black diamonds) and the high- (HVC, red diamonds) velocity components. The points are a median of the values shown in Fig. 6 over the HVC and the LVC. From top to bottom: a) intensity profiles of the [Sii], [Oi], [Nii], and Hαlines integrated over their velocity profile and normalized to their peak intensity b) the electron density, n_e, in units of 10³ cm^-3; c) the ionisation fraction, x_e; d) the temperature, T_e, in units of 10⁴ K; e) the total density, n_H, in units of 10⁴ cm^-3.