  Context. The presence of a magnetic guide field induces several types of
anisotropy in solar wind turbulence. The energy cascade rate between scales in
the inertial range depends strongly on the direction of this magnetic guide
field, splitting the energy cascade according to the parallel and perpendicular
directions with respect to magnetic guide field. Aims. Using more than two
years of Parker Solar Probe (PSP) observations, the isotropy and anisotropy
energy cascade rates are investigated. The variance and normalized fluctuation
ratios, the kinetic and magnetic energies, and the normalized cross-helicity
and residual energy are studied. The connection between the heliocentric
distance, the local temperature of the plasma, and the energy cascade
components is made. Methods. Using exact relations for fully developed
incompressible magnetohydrodynamic (MHD) turbulence, the incompressible energy
cascade rate is computed. In particular, using the isotropy and 2D and slab
assumptions, the isotropic, perpendicular, and parallel energy cascade rate
components are estimated. Results. The variance anisotropy ratios, for both
velocity and magnetic fields, do not exhibit a dependence with respect to the
heliocentric distance $r$ between 0.2 and 0.8 au. While the velocity normalized
fluctuation ratio shows a dependence with $r$, the magnetic normalized
fluctuation ratio does not. A strong correlation between the isotropic and
anisotropic energy cascade rates and the temperature is found. A clear
dominance of the perpendicular cascades over the parallel cascades as PSP
approaches the Sun is observed. A dominant 2D cascade and/or geometry over the
slab component in slow solar wind turbulence in the largest MHD scales is
observed.
