A systematic experimental study of the power, length, and gas pressure
dependence of plasma density and temperature profiles in thermally co
llapsed magnetized helium plasmas has been performed on the Princeton
divertor simulator apparatus. The recombination edge and recombination
radiation from highly excited levels (to n = 12) have been identified
. The importance of radiation and neutral particles to heat transport
has been demonstrated. A region of stable plasma detachment has been f
ound and is suggested as being suitable for divertor operational space
.