We discuss the evolution of ionization instability, which gives rise to the formation of regular structures in plasma. The experiment was conducted in a disk magnetohydrodynamic channel in Xe. The evolution of luminous inhomogeneities, and changes in the luminosities of individual inhomogeneities, are traced. Electron concentrations and temperatures in fluctuations are measured. Average values of the electron concentration and temperature, plasma conductivity, and the Hall parameter are estimated. The average conductivity and Hall parameter are compared with the effective values. The influence of positive and negative fluctuations in plasma parameters on the enhancement of ionization oscillations and average current is analyzed. Based on experimental data, a mechanism is suggested that is responsible for the increase in the effective conductivity of ionizationally unstable inert gas plasma with increasing magnetic induction.