  The condition of linear instability for a converging cylindrical strong shock
wave (SW) in an arbitrary viscous medium is obtained in the limit of a large
stationary SW radius, when it is possible to consider the same Rankine-Hugoniot
jump relations as for the plane SW. This condition of instability is
substantially different from the condition of instability for the plane SW
because a cylindrical SW does not have chiral symmetry in the direction of the
SW velocity (from left to right or vice versa) as in the case of a plane SW.
The exponential growth rate of perturbations for the converging cylindrical SW
is positive only for nonzero viscosity in the limit of high, but finite,
Reynolds numbers as well as for the instability of a plane SW.
