deletions | additions       diff --git a/introduction.tex b/introduction.tex  index ecc940f..6a9bab6 100644  --- a/introduction.tex  +++ b/introduction.tex 
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Recently, there has been increasing evidence that jets from CTTS have a stationary hot (in the MK range), X-ray emitting region only a few tens of AU from the central star (Section~\ref{sect:introxray}). In this article we want to establish recollimation boundary layers between the stellar wind and a disk wind as a viable scenario to explain stationary X-ray and UV emission from YSO jets.  While X-ray emission has been discussed in the literature (Section~\ref{sect:intromodel}), stationary shocks between a stellar wind and a recollimating disk wind have not been investigated in detail.   X-rays trace the fastest and most energetic components of YSO  jets. They can also influence the chemistry deep in the disk \citep[e.g.][]{2010ApJ...714.1511H,2012ApJ...756..157G} and thus alter the environment of planet formation because they penetrate deeper than UV and optical radiation. Unlike stellar X-ray emission, the radiation from the jet originates above the plane of the disk and thus reaches the entire disk surface, while stellar radiation may be shadowed by the inner disk rim. In the remainder of the introduction we review observational properties (including X-ray emission) of jets from CTTS and summarize theoretical explanations for this emission in the literature. In section~\ref{sect:model} we develop the equations that govern a standing shock front and discuss the physical parameters in section~\ref{sect:parameters}. In section~\ref{sect:results} we present our results and discuss implications in section~\ref{sect:discussion}. We summarize this work in section~\ref{sect:summary}.