On the analogy of stability of tangential discontinuities in hydrodynamics and in nonisothermal collisionless plasma

Analogy between stability of tangential discontinuities in an ideal liquid in conventional hydrodynamics and in collisionless nonisothermal plasma with T _e ≫ T _i is shown. The difference is due to specific features of dispersion of ion sound waves in nonisothermal plasma in the short-wavelength range, in which the lasma quasineutrality is violated and the dispersion curve tends to the ion Langmuir frequency.