Almost all sources of high energy particles and photons are associated with jet phenomena .
Prominent sources of such highly relativistic outflows are pulsar winds , Active Galactic Nuclei and Gamma-Ray Bursts .
The current understanding of these jets assumes diluted plasmas which are best described as kinetic phenomena .
In this kinetic description particle acceleration to ultra-relativistic speeds can occur in completely unmagnetized and neutral plasmas through insetting effects of instabilities .
Even though the morphology and nature of particle spectra are understood to a certain extent , the composition of the jets is not known yet .
While Poynting-flux dominated jets ( e.g .
occuring in pulsar winds ) are certainly composed of electron-positron plasmas , the understanding of the governing physics in AGN jets is mostly unclear .

In this article we investigate how the constituting elements of an electron-positron-proton plasmas behave differently under the variation of the fundamental mass-ratio m _ { p } / m _ { e } .

We studied initially unmagnetized counterstreaming plasmas using fully relativistic three-dimensional particle-in-cell simulations to investigate the influence of the mass-ratio on particle acceleration and magnetic field generation in electron-positron-proton plasmas .
We covered a range of mass-ratios m _ { p } / m _ { e } between 1 and 100 with a particle number composition of n _ { p ^ { + } } / n _ { e ^ { + } } of 1 in one stream , therfore called the pair-proton stream .
Protons are injected in the other one , therfore from now on called proton stream , whereas electrons are present in both to guarantee charge neutrality in the simulation box .
We find that with increasing proton mass the instability takes longer to develop and for mass-ratios > 20 the particles seem to be accelerated in two phases which can be accounted to the individual instabilities of the different species .
This means that for high mass ratios the coupling between electrons/positrons and the heavier protons , which occurs in low mass-ratios , disappears .