  We perform a comprehensive investigation of the coupling between a
Rydberg-dressed atomic gas and an ultra-cold plasma. Using simultaneous
time-resolved measurements of both neutral atoms and ions, we show that plasma
formation occurs via a Coulomb anti-blockade mechanism, in which background
ions DC Stark shift nearby atoms into resonance at specific distances. The
result is a highly correlated growth of the Rydberg population that shares some
similarities with that previously observed for van der Waals interactions. We
show that a rate equation model that couples the laser-driven Rydberg gas to
the ultra-cold plasma via a Coulomb anti-blockade mechanism accurately
reproduces both the plasma formation and its subsequent decay. Using long-lived
high angular momentum states as a probe, we also find evidence of a crossover
from Coulomb anti-blockade to Coulomb blockade at high density. As well as
shedding light on loss mechanisms in Rydberg-dressed gases, our results open
new ways to create low-entropy states in ultra-cold plasmas.
