On a fusion chain reaction via suprathermal ions in high-density H–¹¹B plasma

Abstract

The 11B(p,3α) fusion reaction is particularly attractive for energy production purposes because of its aneutronic character and the absence of radioactive species among reactants and products. Its exploitation in the thermonuclear regime, however, appears to be prohibitive due to the low reactivity of the H–11B fuel at temperatures up to 100 keV. A fusion chain sustained by elastic collisions between the α particles and fuel ions, this way scattered to suprathermal energies, has been proposed as a possible route to overcome this limitation. Based on a simple model, this work investigates the reproduction process in an infinite, non-degenerate H–11B plasma, in a wide range of densities and temperatures which are of interest for laser-driven experiments ( 10 24 ≲ n e ≲ 10 28 cm − 3 , T e ≲ 100 keV , T i ∼ 1 keV ). In particular, cross section data for the α–p scattering which include the nuclear interaction have been used. The multiplication factor, k ∞ , increases markedly with electron temperature and less significantly with plasma density. However, even at the highest temperature and density considered, and despite a more than twofold increase by the inclusion of the nuclear scattering, k ∞ turns out to be of the order of 10−2 only. In general, values of k ∞ very close to 1 are needed in a confined scheme to enhance the suprathermal-to-thermonuclear energy yield by factors of up to 103 or 104.

In-Target Proton–Boron Nuclear Fusion Using a PW-Class Laser

“…In the last 15 years, p-B fusion has been effectively induced by means of high-power lasers, which has reported an impressive progression in the reaction yield [2,4,7,8], thus has become a point of interest for the energy sector where it is being considered as an alternative approach to conventional inertial confinement fusion schemes [9][10][11] and also potentially for medicine where intense α-particle beams can be used for radioisotope production [12]. However, an extensive systematic investigation of laser-based p-B fusion of the deep understanding of the underpinning physics is still missing [13]. An overview of the recent experimental progression in p-B fusion in terms of α-particle flux (or flux per input laser energy) is shown in Figure 1, both for the "in-target" [2][3][4]7,14] and "pitcher-catcher" geometries [5,6,8,15].…”

Analysis of the p-11B Fusion Scenario with Compensation of the Transfer of Kinetic Energy of Protons and Alpha Particles to the Gas Medium by the Electric Field

“…Eliezer et al [10] analyzed the situations when reaction (1) occurs in gaseous H 3 11 B or other hydride of 11 B with a density of 10 19 cm −3 or of the order of 10 19 cm −3 and temperature of about 1 eV or few eV. Ionization of this gas is supposed negligible [10].…”

“…is discussed since 1973 [1][2][3][4][5][6][7][8][9][10][11][12]. One of the chain reactions consists of the scattering of at least one of the three alpha particles, generated by reaction (1), on proton(s) with acceleration of the proton(s) to kinetic energies, corresponding to a relatively high cross-section σ 1 for reaction (1) and the subsequent participation of the accelerated proton(s) in this reaction [1,4,[6][7][8][9][10][11][12]. According to [1], at the temperature of 150-350 keV and the density of 10 16 -10 26 cm − 3 , this chain reaction and other "nonthermal" effects result in an increase in R 1 on 5-15%.…”

“…According to [2-4, 7, 9, 10, 12], at least if special measures are taken, the increase in R 1 due to the chain reactions can be so high that it will provide the possibility of the use of reaction (1) for power production. e negative results of analysis of such assumptions from [2][3][4] are presented in [5,6,8,11].…”

“…In 2020, Eliezer and Martinez-Val [9] and Eliezer et al [10] proposed p-11 B fusion scenarios with the influence of electric and magnetic fields on protons and alpha particles in the gas medium. e main idea of the proposal is that during some time periods, time-dependent electric field should compensate approximately for the transfer of kinetic energy ε p of a proton with ε p ≈ ε * p , where ε * p is ε p corresponding to the largest value of σ 1 for the collision of proton with the nucleus of 11 B in the rest, to the medium and for transfer of the kinetic energy of the alpha particle to the medium [9,10].…”