We investigate the temporal evolution of the current pulses from an ac He cold plasma jet at atmospheric pressure and with driving frequency in the range 14.76-15.30 kHz. The driving frequency is used as the plasma systems bifurcation parameter in analogy with the evolution in which the current pulses undergoes multiplication and chaos. Such time-domain nonlinearity is important for controlling instabilities in atmospheric glow discharges.In addition, the observation can provide some data to support the simulation results reported previously [Appl.Phys. Lett. 90 (2007) 071501].