  The impact of ram pressure stripping on galaxy evolution is well known.
Recent multi-wavelength data have revealed many examples of galaxies undergoing
stripping, often accompanied with multi-phase tails. As energy transfer in the
multi-phase medium is an outstanding question in astrophysics, galaxies in
stripping are great objects to study. Despite the recent burst of observational
evidence, the relationship between gas in different phases in the tails is
poorly known. Here we report a strong linear correlation between the X-ray
surface brightness and the H$\alpha$ surface brightness of the diffuse gas in
the stripped tails at $\sim$ 10 - 40 kpc scales, with a slope of $\sim$ 3.5.
This discovery provides evidence for the mixing of the stripped interstellar
medium with the hot intracluster medium as the origin of the multi-phase tails.
The established relation in stripped tails, also in comparison with the likely
related correlations in similar environments like galactic winds and X-ray cool
cores, provides an important test for models of energy transfer in the
multi-phase gas. It also indicates the importance of the H$\alpha$ data to
study clumping and turbulence in the intracluster medium.
