Numerical simulation of proton generation with continuous energy spectrum by pulse Jantage with discrete steps

The performance degradation of spacecraft thermal control coatings irradiated by protons is generally investigated by using protons with the same energy in ground testing while the energy of protons is in succession in space. The irradiation equivalence of the two kinds of protons is still not well understood. In this paper, a method of producing protons with continuous energy by plasma sheath acceleration using pulse Jantage with discrete steps is proposed for better analysis of irradiation equivalence. The dose-energy distribution on the sample is numerically investigated by particle-in-cell (PIC) method. The characteristics of dose-energy distribution and the formation mechanism of protons with continuous energy are then discussed. The results show that protons with continuous energy can be realized utilizing pulse Jantage with discrete steps, as the energy of protons irradiating the sample overlaps between two adjacent 1 μs periods, and the energy of protons produced is closely related to the Jantage on the sample in every 1 μs period. Moreover, the number of protons irradiating the sample may decrease if the proton energy increases. (authors)