  Coulomb final-state interaction of positive charged kaons in heavy ion
reactions and its impact on the kaon transverse flow and the kaon azimuthal
distribution are investigated within the framework of QMD (Quantum Molecular
Dynamics) model. The Coulomb interaction is found to tend to draw the flow of
kaons away from that of nucleons and lead to a more isotropic azimuthal
distribution of kaons in the target rapidity region. The recent FOPI data have
been analyzed by taking into accout both the Coulomb interaction and a kaon
in-medium potential of the strong interaction. It is found that both the
calculated kaon flows with only the Coulomb interaction and with both the
Coulomb interaction and the strong potential agree within the error bars with
the data. The kaon azimuthal distribution exhibits asymmetries of similar
magnitude in both theoretical approaches. This means, the inclusion of the
Coulomb potential makes it more difficult to extract information of the kaon
mean field potential in nuclear matter from the kaon flow and azimuthal
distribution data.
