Using the Chandra HETG spectrum of EX Hya as an example , we discuss some of the plasma diagnostics available in high-resolution X-ray spectra of magnetic cataclysmic variables .
Specifically , for conditions appropriate to collisional ionization equilibrium plasmas , we discuss the temperature dependence of the H- to He-like line intensity ratios and the density and photoexcitation dependence of the He-like R line ratios and the Fe XVII I ( 17.10 ~ { } { \AA } ) / I ( 17.05 ~ { } { \AA } ) line ratio .
We show that the plasma temperature in EX Hya spans the range from \approx 0.5 to \approx 10 keV and that the plasma density n { \lower 3.225 pt \hbox { $ > $ } \atop \raise 2.15 pt \hbox { $ \sim$ } } 2 \times 10 ^ { 14 } ~% { } cm ^ { -3 } , orders of magnitude greater than that observed in the Sun or other late-type stars .