Studying Magnetic Accretion on EX Hya Using the Chandra HETG

In magnetic cataclysmic variables, the primary is a white dwarf whose

strong magnetic field controls the accretion flow close to the white

dwarf, leading to a shock and accretion columns that radiate strongly

in X-rays. The archival Chandra HETG spectrum of the eclipsing system

EX Hya shows strong line emission from the plasma as it cools from the

shock to the white dwarf surface. A spin phase-folded light curve formed from Mg XI

shows two spikes not found in the Mg XII or broad-band light

curves. These spikes appear during spin phases when neither column is

occulted by the white dwarf and thus constrain the height at which the

Mg XI is formed. We demonstrate that high resolution X-ray spectra can

be used to map the temperature and density structure of the accretion

flow.