Structure and Feedback in 30 Doradus II. Structure and Chemical
  Abundances
  We use our new optical-imaging and spectrophotometric survey of key
diagnostic emission lines in 30 Doradus, together with CLOUDY photoionization
models, to study the physical conditions and ionization mechanisms along over
4000 individual lines of sight at points spread across the face of the extended
nebula, out to a projected radius 75 pc from R136 at the center of the ionizing
cluster NGC 2070. We focus on the physical conditions, geometry and importance
of radiation pressure on a point-by-point basis, with the aim of setting
observational constraints on important feedback processes. We find that the
dynamics and large scale structure of 30 Dor are set by a confined system of
X-ray bubbles in rough pressure equilibrium with each other and with the
confining molecular gas. Although the warm (10,000K) gas is photoionized by the
massive young stars in NGC 2070, the radiation pressure does not currently play
a major role in shaping the overall structure. The completeness of our survey
also allows us to create a composite spectrum of 30 Doradus, simulating the
observable spectrum of a spatially-unresolved, distant giant extragalactic H II
region. We find that the highly simplified models used in the "strong line"
abundance technique do in fact reproduce our observed lines strengths and
deduced chemical abundances, in spite of the more than one order of magnitude
range in the ionization parameter and density of the actual gas in 30 Dor.
