Abstract
Observations of pulsar scintillation are among the few astrophysical probes
of very small-scale ($\lesssim$ au) phenomena in the interstellar medium (ISM).
In particular, characterization of scintillation arcs, including their
curvature and intensity distributions, can be related to interstellar
turbulence and potentially over-pressurized plasma in local ISM
inhomogeneities, such as supernova remnants, HII regions, and bow shocks. Here
we present a survey of eight pulsars conducted at the Five-hundred-meter
Aperture Spherical Telescope (FAST), revealing a diverse range of scintillation
arc characteristics at high sensitivity. These observations reveal more arcs
than measured previously for our sample. At least nine arcs are observed toward
B1929$+$10 at screen distances spanning $\sim 90\%$ of the pulsar's $361$ pc
path-length to the observer. Four arcs are observed toward B0355$+$54, with one
arc yielding a screen distance as close as $\sim10^5$ au ($<1$ pc) from either
the pulsar or the observer. Several pulsars show highly truncated,
low-curvature arcs that may be attributable to scattering near the pulsar. The
scattering screen constraints are synthesized with continuum maps of the local
ISM and other well-characterized pulsar scintillation arcs, yielding a
three-dimensional view of the scattering media in context.