Analysis of suprathermal nuclear processes in the solar core plasma

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 ⁷(p,α) α reaction of the pp chain, and to analyze suprathermal processes in the solar CNO cycle induced by them. Particular attention is paid to the suprathermal¹⁴(α,p) ¹⁷ 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 R > 0.1R_⊙, normal branching of nuclear flow ¹⁴N ← ¹⁷O → ¹⁸O transforms to abnormal sequential flow ¹⁴N ← ¹⁷O → ¹⁸O, 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 (α,p) reactions may also affect abundances of CNO elements, including those generating solar neutrinos.