  This paper reports the Suzaku results on the northeast shell of RCW 86. With
the spatial and spectral analysis, we separated the X-rays into three distinct
components; low (kT_e~0.3keV) and high (kT_e~1.8keV) temperature plasmas and a
non-thermal component, and discovered their spatial distributions are different
from each other. The low temperature plasma is dominated at the east rim,
whereas the non-thermal emission is the brightest at the northeast rim which is
spatially connected from the east rim. The high temperature plasma, found to
contain the ~6.42keV line (K alpha of low-ionized iron), is enhanced at the
inward region with respect to the east rim and has no spatial correlation with
the non-thermal X-ray (the northeast). The Fe-Kalpha line, therefore, is not
related to the non-thermal emission but originates from Fe-rich ejecta heated
to the high temperatures by the reverse shock. Since the metal abundances of
the low temperature plasma are sub-solar, the most possible origin of this
component is interstellar medium heated by a blast wave. The non-thermal X-ray,
which has a power-law index of ~2.8, is likely to be synchrotron emission. A
possible scenario to explain these morphologies and spectra is: A fast moving
blast wave in a thin cavity of OB association collided with a dense
interstellar medium or cloud at the east region very recently. As the result,
the reverse shock in this interior decelerated, and arrived at the Fe-rich
region of the ejecta and heated it. In the northeast rim, on the other hand,
the blast wave is still moving fast, and accelerated high energy electrons to
emit synchrotron X-rays.
