The time evolution of the matter parameters and current distribution in the discharge channel formed during a nanosecond explosion of a 25 µm diameter 12 mm long aluminum wire was studied in a series of experiments with the following parameters: the discharge voltage was U 0 = 20 kV, the current ampli tude was I max ~ 8 kA, and the current rise rate was dI/dt ~ 40 A/ns. Optical shadow and schlieren images of the discharge channel were obtained using the second harmonic of a YAG : Nd +3 laser, and UV images of the discharge channel self radiation were recorded using a four frame camera with a microchannel plate. The process of aluminum wire explosion was simulated numerically (including simulations performed from the "cold start"). The numerical results were compared with the experimental data.