# Effect(s) of different species in shock waves

In air, transitioning from a local mach number ($$M$$) of $$M > 1$$ to $$M < 1$$ produces a shock. But $$M$$ is defined simply based on the velocity of an object relative to the local speed of sound. If a positron-electron gas is introduced into air, moving at supersonic speeds, will a shock be produced? The original air and injected gas species no long have similar masses, and I'm simply curious if a shock would be produced in such a scenario where the individual positrons and electrons may have significantly lower momentum than the gas particles, but are nevertheless moving faster than the local air's speed of sound.

I think you are thinking about partial pressures (if not, you should be) because the speed of sound is defined as: $$C_{s}^{2} = \frac{ \partial P }{ \partial \rho }$$ where $$P = \sum_{s} P_{s}$$ is the total gas pressure summed over all species $$s$$ and $$\rho$$ is the average mass density of the gas.