Resonant Weibel instability in counterstreaming plasmas with temperature anisotropies

The Weibel instability driven by plasma temperature anisotropy, is non-resonant with plasma particles: it is purely growing in time, and does not oscillate The effect of a, counterstreaming plasma, is examined. In a, counterstreaming plasma with all excess of transverse temperature, the Weibel instability arises along the streaming direction Here it is proved that Or large wave-numbers the instability becomes resonant with a finite real (oscillation) frequency, omega(r) not equal 0. When the plasma, flows faster, with a bulk velocity larger than the parallel thermal velocity, the instability becomes dominantly resonant. This new feature of the, Weibel instability can be relevant for astrophysical sources of non-thermal emissions and the stability of counterflowing plasma experiments.status: publishe