  A consistent model for the description of non-Maxwellian nuclear processes in
the solar core triggered by fast reaction-produced particles is formulated. It
essentially extends an approach to study suprathermal solar reactions discussed
previously [Phys. Rev. C 91, 028801 (2015)] and refines its predictions. The
model is applied to examine in detail the slowing-down of 8.7-MeV alpha
particles produced in the 7Li(p,alpha)alpha reaction of the pp chain, and to
study suprathermal processes in the solar CNO cycle induced by them. The
influence of electron degeneracy and electron screening on suprathermal
reactions through in-flight reaction probability and fast particle emission
rate is clarified. In particular, these effects account for a 20% increase of
the 14N(alpha,p)17O reaction rate at R < 0.2Rsun. This new type of correction
is important for the suprathermal reaction like 14N(alpha,p)17O as it is
recognized to be capable of distorting the CNO cycle in the 95% region of the
solar core. In this region, normal branching 14N <-- 17O --> 18F of nuclear
flow transforms to abnormal sequential flow 14N --> 17O --> 18F, and the
14N(alpha,p)17O reaction rate exceeds the rate of 17O burn up through
conventional 17O(p,alpha)14N and 17O(p,gamma)18F processes. It is shown that
these factors can enhance the 17O abundance in the core as compared with
standard estimates. For the steady state case, the abundance enhancement is
estimated to be as high as ~ 100 in the outer core region. A conjecture is made
that other CNO suprathermal (alpha,p) reactions may also alter abundances of
CNO elements, including those generating solar neutrinos.
