  The Interstellar Boundary Explorer (IBEX) images the heliosphere by observing
energetic neutral atoms (ENAs). The IBEX-Hi instrument onboard IBEX provides
full-sky maps of ENA fluxes produced in the heliosphere and very local
interstellar medium (VLISM) through charge exchange of suprathermal ions with
interstellar neutral atoms. The first IBEX-Hi results showed that in addition
to the anticipated globally distributed flux (GDF), a narrow and bright
emission from a circular region in the sky, dubbed the IBEX ribbon, is visible
in all energy steps. While the GDF is mainly produced in the inner heliosheath,
ample evidence indicates that the ribbon forms outside the heliopause in the
regions where the interstellar magnetic field is perpendicular to the lines of
sight. The IBEX maps produced by the mission team distribute the observations
into $6\deg\times6\deg$ rectangle pixels in ecliptic coordinates. The overlap
of the GDF and ribbon components complicates qualitative analyses of each
source. Here, we find the spherical harmonic representation of the IBEX maps,
separating the GDF and ribbon components. This representation describes the ENA
flux components in the sky without relying on any pixelization scheme. Using
this separation, we discuss the temporal evolution of each component over the
solar cycle. We find that the GDF is characterized by larger spatial scale
structures than the ribbon. However, we identify two isolated, small-scale
signals in the GDF region that require further study.
