Question about kinetic theory and hydrodynamics (in plasmas)

[zaki belh]

It is usual, in plasma physics, to combine the kinetic description for electron fluid and the hydrodynamic description for ion fluid, when studying the plasma properties or the dynamics of the electrostatic waves.
I am wondering what are the physical meaning and limits of such an approach.
Thanks.

 

[jasonRF]

I find your question curious. In what context do you find it is “usual” to use kinetic theory for electrons and fluid theory for ions?I did my PhD in plasma physics and do not recall seeing this approach. All of my research was on space plasmas, but the pure plasma physics coursework I took was general since it was taken by students with many interests (fusion, space physics, semiconductor processing, etc).