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   51083
   The high-energy, relativistic jet ejected from SS433 collides with the
   shell of W50, the supernova remnant surrounding SS433, in $10^{2-3}$ yr
   after the ejection. As the result of the interaction of the jet and
   shell, the X-ray lobe is formed. The front shock of the collision
   compresses and heats the shell matter. Therefore, the shell matter is
   expected to emit thermal X-ray, which is detectable by ASCA. We propose
   to observe the end of the lobe to reveal the thermal nature of it. The
   thermal emission would give us variety of information on the physics of
   the jet, shell, and interstellar matter. This study is directly
   applicable to the interaction of pulsar winds and environments.
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