On the evaluation of ignition threshold in proton‐carbon hybrid ignitor beam proposal

Abstract

We may improve plasma ignition quality in a conically guided proton fast ignition scheme by the application of an extra lower intensity, secondary carbon beam. According to the experimental measurements on the number of laser-accelerated ions, the temporal evolution of the hot spot electron, ion, and radiation temperatures was examined using three-temperature plasma model, in radiation pressure acceleration (RPA) mechanisms for a proton-Carbon beam configuration, E avg ≈ 10 MeV/nucleon. The hot spot ignition was evaluated by the well-known stopping power models proposed independently by Li-Petrasso (LP) and Brown-Preston-Singleton (BPS). Based on our analytical results, with time, plasma temperature in the LP model surpasses the BPS model. From this point of view, to compensate this deficiency in the BPS method, we will show that the density ratio of 17% is required when the energy spread is 10%. The results were also validated by the DEIRA-4 code. Moreover, the electron-ion equilibrium will decrease up to 9.3 and 4.4% for the LP and BPS methods, respectively. It is demonstrated that the key features of a higher average ion energy as well as the narrow beam profile in the RPA regime may effectively ignite hot spot much better than in the Target Normal Sheath Acceleration (TNSA) counterpart. It is estimated that the proton-Carbon beam proposal can reduce ion beam energy to 8.42 kJ, approximately saving 15% of ignitor energy. K E Y W O R D Sconically guided fast ignition, laser-accelerated ion beam, proton and carbon beam, RPA, TNSA

Simulation study of cone-in-shell target for indirect-drive ion fast ignition concept under the theory of an effective interaction potential

“…In order to ignite an imploded fuel, the incident beam must be irradiated the target at the times of less than the hydrodynamic equilibrium time (τ eq ) 60 . Otherwise, as the plasma target expands, it will not have the density required to initiate ignition procedure.…”

Efficient proton-carbon ions acceleration by the plasma-beat-wave mechanism in the presence of the axial magnetic field

“…The latter was first clarified by Temporal in 2006, where the improvement of deuterium-tritium (DT)-fusion conditions was confirmed using the idea of a two-beam scheme [28]. Recently, with the advantage of multiple proton-carbon species produced through the laser-foil interaction, the hybrid ignitor fast ignition proposed by Mehrangiz and Khoshbinfar [35]. It has been shown that the multiple proton-carbon beam proposal reduces the beam energy to 8.42 kJ, which can efficiently save about 15% of ignitor energy, compared to the default 10 kJ.…”