  Limiting ourselves to two flavor approximation the motion of the neutrino
flux in the solar matter and twisting magnetic field is considered. For the
neutrino system described by the 4-component wave function $\Psi^T = (\nu_{eL},
\nu_{XL}, {\overline\nu}_{eR}, {\overline\nu}_{XL})$, where $X=\mu, \tau$, an
evolution equation is found. Our consideration carries general character, that
is, it holds for any SM extensions with massive neutrinos. The resonance
transitions of the electron neutrinos are investigated. Factors which influence
on the electron neutrino flux, crossing a region of solar flares (SF) are
defined. When the SF is absent a terrestrial detector records the electron
neutrino flux weakened at the cost both of vacuum oscillations and of the MSW
resonance conversion only. On the other hand, the electron neutrino flux passed
the SF region in preflare period proves to be further weakened in so far as it
undergoes one (Majorana neutrino) or two (Dirac neutrino) additional resonance
conversions, apart from the MSW resonance and vacuum oscillations. The
hypothesis of the $\nu_e$-induced decays which states that decreasing the beta
decay rates of some elements of the periodic table is caused by reduction of
the solar neutrino flux is discussed as well.
  PACS number(s): 12.60.Cn, 14.60.Pg, 96.60.Kx, 95.85.Qx, 96.60.Rd.
