  Taking a clue from their sharp-edged (strip-like) morphology observed in
several cases, a new mechanism is proposed for the formation of the emission
gaps seen between the radio lobes of many powerful extragalactic double radio
sources. Canonical understanding of the radio gaps invokes either blocking of
the back-flowing lobe plasma by the denser interstellar medium (ISM) of the
host galaxy, or "squeezing" of the radio bridge in the middle through buoyancy
force exerted by either the ISM or the surrounding intra-cluster medium (ICM).
These pictures encounter difficulties in explaining situations where the
sharp-edged radio gaps associated with non-cluster radio galaxies have widths
running into several tens (even hundreds) of kiloparsecs. More particularly,
the required dense high-pressure ISM/ICM is likely to be lacking at least in
the case of high-redshift radio galaxies. We propose here that radio emission
gaps in at least such cases could arise from a dynamical interaction between
the powerful thermal wind outflowing from the active galactic nucleus and the
back-flowing synchrotron plasma in the two radio lobes, which occurs once the
rapidly advancing jets have crossed out of the wind zone into the intergalactic
medium. A simple analytical scheme is presented to explore the plausibility of
the side-ways confinement of the thermal wind by the radio lobe pair, which
would "freeze" pancake shaped conduits in the space, along which the hot, metal
enriched wind from the AGN can escape (roughly orthogonal to the radio axis).
Some other possible consequences of this scenario are pointed out.
