Radio-loud AGN-jet morphology and polarization: the role of ultra-high
  resolution radio surveys
  A review of the current challenges for the understanding of the physics of
extragalactic radio jets from supermassive black holes is presented. Also, a
prospect is given about how both very long baseline interferometry (VLBI) and
polarimetric observations help us to understand their physics and the ones of
their magnetic fields. This paper focuses on the impact that previous
ultra-high resolution polarimetric surveys have had on our current knowledge on
radio loud AGN. It first concentrates on the expectations about the improvement
that the Square Kilometer Array, used as a super-sensitive VLBI station on
existing and future very long baseline interferometric arrays, will provide in
terms of access to new source classes, and in terms of a deeper portion of the
Universe than currently accessible. A series of key new radio loud AGN science
fields, to be opened by the Square Kilometer Array, are outlined together with
a collection of preliminary ideas about possible programs of interest to deep
in such fields. The complementary aspects of future super-sensitive VLBI
observations as compared to deep continuum surveys with the Square Kilometer
Array and its precursors are also outlined here.
