Hot electron model for ion emission (Hermione): an effective model for target normal sheath acceleration ion spectra from femtosecond to picosecond lasers

Recent advances in high-power lasers for secondary particle generation highlight the need for reliable and affordable particle sources. In laser-driven ion acceleration, the most routinely obtainable acceleration mechanism is the so-called Target Normal Sheath Acceleration (TNSA) mechanism. Predicting the characteristics of particle sources produced through this mechanism is essential for modeling experiments at existing and future laser facilities. In this work, we present a versatile and fast predictive model, Hermione, capable of reproducing proton spectra across several laser facilities, including the laser facilities PETAL, Apollon, LFEX, and ALLS. Our results show very good agreement with experimental data for laser pulses longer than 100 fs, while a slight overestimation of the proton yield is observed for shorter pulses (<100 fs). We also demonstrate the model’s ability to reproduce wavelength-dependent effects for lasers operating between 0.8 μ m and 2 μ m. Hermione delivers results on very short timescales (less than 1 minute on a standard laptop), making it an efficient complementary tool to more complex and computationally demanding Particle-In-Cell (PIC) simulations. This enables rapid optimization of the TNSA acceleration regime by varying laser energy, pulse duration, and focal spot size. The code is open access, allowing the community to refine and adapt it to specific applications.