The permutation entropy concept of Bandt and Pompe (2002 Phys. Rev. Lett.88 174102) is used to analyze the fluctuations in ion saturation current that spontaneously arise in a basic experimental study (Pace et al 2008 Phys. Plasmas15 122304) of electron heat transport in a magnetized plasma. From the behavior of the Shannon entropy and the Jensen–Shannon complexity it is found that the underlying dynamics are chaotic rather than stochastic. A partitioning and scrambling technique is used to demonstrate that the exponential character of the associated power spectrum arises from individual Lorentzian pulses observed in the time series.