Constraints on shock physics, wind structure, and dynamics from high-resolution X-ray spectroscopy of massive stars

High-resolution X-ray spectroscopy provides detailed information about the shock physics, spatial structure, and kinematics of 
the winds and magnetospheres of hot, massive stars.  In this talk, I will discuss the constraints that high-resolution X-ray 
spectra of normal, non-magnetic O supergiants place on models of embedded wind shocks that arise due to the 
line-deshadowing instability.  Specifically, X-ray line profiles, line ratios, and the lack of time variability confirm that  numerous 
separate shock-heated volumes are distributed throughout the wind above an onset radius of roughly 1.5 stellar radii, and that 
their kinematics are similar to that of the bulk wind. These same X-ray line profiles, in conjunction with density-squared 
diagnostics from other spectral regions, indicate that massive star winds have numerous small clumps, with overdensity 
factors of order 10.  However, the observed line profiles show no evidence for large-scale wind porosity.  For the very few 
magnetic massive stars with available high-resolution X-ray spectra, there is evidence for stronger shocks, hotter plasma, and 
in some cases, narrower lines and thus slower moving shock-heated plasma, perhaps confined in the magnetosphere.  
However, not all of the observed X-ray properties of magnetic massive stars can be easily understood in the context of a 
simple magnetically confined wind shock scenario.