Two overrun phenomena and their effects on fusion yield in the Coulomb explosion of heteronuclear clusters

Abstract

Two overrun effects in the Coulomb explosion dynamics of heteronuclear clusters have been investigated theoretically by the use of a simplified electrostatic model. When the charge-to-mass ratio of light ions is higher than that of heavy ions, the light ions can overtake the heavy ions inside the cluster and acquire a higher kinetic energy. Further, if the charge density of the heavy ions is twice as high as that of the light ions, i.e. a proposed competitive parameter ζ = ρBqB/ρAqA > 2, the inner light ions can overtake those light ions on the surface of the cluster and form a shock shell during the explosion, which might drive the intracluster collision and fusion of the light ions. Different regimes of nuclear fusion are discussed and the corresponding neutron yields are estimated. Our analysis indicates that the probability of intracluster fusion is quite low even if deuterated heteronuclear clusters such as (DI)n with large size and high competitive parameter are employed. However, heteronuclear clusters are still a better candidate compared with homonuclear clusters for enhancing the total intercluster fusion yield because both a higher energy region and a higher proportion of deuterons distributing in the energy region can be created in the deuterated heteronuclear clusters.

Study on Coulomb explosions of ion mixtures

“…Exploiting the hypothesis of no overtakings among ions of the same species and the new approach based on the linear behavior for the electric field inside the inner sphere, S s , containing both slow and fast ions, analytical formulas describing the acceleration both inside and outside S s (where only fast ions are present), have been derived together with the energy spectrum. For the first time (at least to the Authors' knowledge), a simple way to deduce if overtakings between fast ions will take place during the expansion is presented and discussed, confirming the existence, empirically deduced in a previous work by using numerical simulations (Li et al, 2007), of a limit value for the mixture composition, α crit , above which no shocks are forming. The analysis here proposed is based on the calculation of the derivative of ∞ with respect to the initial ion position r 0 : when this quantity is negative for some r 0 , the hypothesis of no overtaking is no longer valid.…”

“…In summary, the condition Q f = Q s /2 is valid in any case and can be used in order to discriminate between explosions with and without shocks. This is the rigorous proof of a property of the Coulomb explosions of mixtures that was found numerically in a previous work (Li et al, 2007). The condition Q f = Q s /2 provides the critical value of α:…”

“…from which the energy spectrum can be readily calculated (Li et al, 2007;Murakami & Mima, 2009). Two situations can occur, depending on the sign of Q f −Q s /2.…”

Coulomb explosion of nanodroplets drives the conversion of laser energy to nuclear energy

“…Table-top nuclear fusion in the chemical physics laboratory [1,2] was realized by nuclear fusion driven by Coulomb explosion (NFDCE) of assemblies of nanostructures, i.e., clusters (with initial radii R 0 = 1-10 nm) [3][4][5][6][7][8][9][10][11][12][13][14][15] , and nanodroplets (with R 0 = 10-500 nm) [15][16][17][18][19][20] , which are driven by ultraintense femtosecond near-infrared lasers [7,8,17] . The ultraintense laser pulses for generating Coulomb explosion (CE) of such nanostructures are characterized by ultrahigh intensities of up to 10 21 W · cm −2 , which can be produced from the currently available Terawatt and Pentawatt lasers [21] .…”

“…The ultraintense laser pulses for generating Coulomb explosion (CE) of such nanostructures are characterized by ultrahigh intensities of up to 10 21 W · cm −2 , which can be produced from the currently available Terawatt and Pentawatt lasers [21] . The interaction of ultraintense femtosecond near-infrared lasers with nanometer-sized matter [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] results in inner and outer ionization of the nanostructures [22][23][24] followed by CE, which produces high-energy (10 keV-15 MeV) ions in the energy domain of nuclear physics. Previous studies of NFDCE of clusters [2][3][4][5][6][7][8][9][10][11][12][13][14][15] and of nanodroplets [17][18][19][20]24] involved nuclear reactions inside or outside the macroscopic plasma filament, which is produced by an assembly of Coulomb-exploding nanostructures within the focal volume of the laser.…”