Analysis of suprathermal nuclear processes in the solar core plasma

Abstract

A consistent model for the description of suprathermal processes in the solar core plasma naturally triggered by fast particles generated in exoergic nuclear reactions is formulated. This model, based on the formalism of in-flight reaction probability, operates with different methods of treating particle slow-down in the plasma, and allows for the influence of electron degeneracy and electron screening on processes in the matter. The model is applied to examine slowing-down of 8.7 MeV α-particles produced in the reaction of the pp chain, and to analyze suprathermal processes in the solar CNO cycle induced by them. Particular attention is paid to the suprathermal reaction unappreciated in standard solar model simulations. It is found that an appreciable non-standard nuclear flow due to this reaction appears in the matter and modifies running of the CNO cycle in ∼95% of the solar core region. In this region at , normal branching of nuclear flow transforms to abnormal sequential flow , altering some element abundances. In particular, nuclear network calculations reveal that in the outer core the abundances of 17O and 18O isotopes can increase by a factor of 20 as compared with standard estimates. A conjecture is made that other CNO suprathermal reactions may also affect abundances of CNO elements, including those generating solar neutrinos.

Suprathermal nuclear effects in the solar core: overall view

“…As in the previous studies [9][10][11], the element mass fractions X i and the temperature T predicted by MESA [32] are employed to calculate the thermal and suprathermal reaction rates. For convenience, the corresponding number densities n i for all reactants in table 1 and the temperature at several radii R R  are presented in Table A1 in the appendix.…”

“…The model described in detail in [10] is used to calculate the solar reaction rates. For the reader's convenience, the basic points of this model are briefly summarized below.…”

“…Suprathermal processes in the solar core triggered by fast nonthermalized products of nuclear reactions were discussed recently in [9][10][11]. The main objective was to realize whether such processes induced by MeV α-particles born in pp chain reactions can affect the running of the CNO cycle.…”

“…The studies [9][10][11] show that the fast α-particles are able to induce a strong suprathermal (α, p) reaction which can redirect nuclear flow from 14 N ¬ 17 O to 14 N  17 O in the CNO cycle, ultimately increasing 17 O and 18 O abundances in the outer core. These results seem particularly interesting because the changes obtained are caused by only one suprathermal process-14 N(α, p) 17 O.…”

Geo-neutrino, Earth heat flux, Earth electricity

“…On the contrary, if we believe that 2% of K in the Earth mass is correct idea the CNO neutrino flux must be lower than the Standard Solar Model CNO neutrino flux. Refer here to results of works [5], [6] in which the authors introduce the idea about fast α particles appearing in nuclear processes in solar core plasma. The reactions of these α particles with CNO nuclei can suppress the CNO neutrino flux.…”