Comments on “Initiation of Pulsed Corona Discharge Under Supercritical Conditions”

While the work of Lock et al. (2005) is interesting, there is a problem with Fig. 3 and the associated text. First, there can be no confident use of an extrapolation from results in the range 6-16 MPa-mum to results at 400 Mpa-mum. Second, there is no validity in plotting corona onset voltages against (pressure) times (electrode radius) and comparing them with breakdown voltages plotted against (pressure) times (electrode separation). Possible alternative experimental approaches that do not violate Paschen's law are suggested