  We present the analysis and interpretation of an observation of the flare
star AD Leo (dM3e) with Chandra/LETG. The high resolution X-ray spectrum
allowed us to infer the plasma emission measure distribution (EMD) vs.
temperature, and the abundances of individual elements in the corona of this
magnetically-active star, during a typical state characterized by significant
variability but no large flaring event. We have also measured plasma densities
at various temperatures using spectroscopic diagnostics provided by He-like
triplets and Fe XXI lines. We show that the present EMD is similar to those
previously obtained from EUVE spectra during quiescent and flaring states,
confirming the long-term stability of the corona of AD Leo. At variance with
the case of other active stars, the EMD of AD Leo is characterized by a
significantly shallower slope, compatible with that predicted by static models
of isobaric loops with constant cross-section and uniform heating. We discuss
such coronal modeling to infer the average properties of the corona in terms of
loop populations, including estimates of the surface filling factor. We also
show that the EMD is compatible with the model of a corona continuously heated
by flares. The coronal composition is such that the element abundances,
relative to solar values, tend to increase with the First Ionization Potential,
with few exceptions. The line to continuum ratios suggest a nearly solar
coronal metallicity.
