  A higher-order multiscale analysis of spatial anisotropy in inertial range
magnetohydrodynamic turbulence is presented using measurements from the STEREO
spacecraft in fast ambient solar wind. We show for the first time that, when
measuring parallel to the local magnetic field direction, the full statistical
signature of the magnetic and Els\"asser field fluctuations is that of a
non-Gaussian globally scale-invariant process. This is distinct from the
classic multi-exponent statistics observed when the local magnetic field is
perpendicular to the flow direction. These observations are interpreted as
evidence for the weakness, or absence, of a parallel magnetofluid turbulence
energy cascade. As such, these results present strong observational constraints
on the statistical nature of intermittency in turbulent plasmas.
