On the possible acceleration and temporary confinement of energetic ions in the distant heliosphereстатья
Статья опубликована в высокорейтинговом журнале
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Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
Аннотация:Theoretical aspects of the energetic ion motions in the magnetic dip between
travelling heliospheric magnetic field perturbations and the termination boundaries
of the heliosphere are considered. The group of ions from the seed population
under appropriate initial conditions perform here several bouncing oscillations and
could be accelerated along the strongly inclined magnetic fields pointed nearly
perpendicular to the radial direction. Accelerating ions are partially confined
between the converging magnetic mirrors at the periphery of the heliosphere
before escaping in the interstellar medium. We develop a tentative model of these
Fermi-type processes which might be useful for the interpretation of recent
Voyager 1, 2 observations. The model is capable to reproduce qualitatively the
following observed features: 1) the reappearance of MeV proton increases several
times during 2000-2004 at both or only at one spacecraft because of the solar and
heliospheric magnetic field “breathing” due to variations of the solar activity; 2)
the time delays between corresponding Voyager 1 and Voyager 2 increases for 3-4
months due to the solar wind propagation; 3) the moderate anisotropy of MeV ion
fluxes directed mainly along the magnetic field spirals away from the Sun; 4) the
possibility of stronger increases of MeV fluxes at larger heliospheric distances, as
was observed in 2003 and 2004, due to the combination of the local acceleration,
partial trapping and propagation effects in the variable electric and magnetic fields.