ION-ION STREAMING INSTABILITY IN A HIGH BETA PLASMA
The criterion Vd/VA<(1+βe)1/2 for instability mentioned in the existing theories is based on the assumption βi《 1. The present study investigates the effects of finite βe and βi on the ion-ion streaming instability. It is found that within the domains under investigation in the parameter space the growth rate increases with the increase of βe. Moreover, the unstable region, as a function of the streaming velocity Vd/VA, becomes broader. On the other hand, when βi increases (for a given βe) the unstable region in the Vd/VA space becomes narrower.
Tailoring the properties of an optical beam incident on a one dimensional metallic grating can attain a substantial control ::: over the excited surface plasmon polariton wave. In this work we derive the complete analytical relations between the ::: optical angles of incidence and the resulting surface plasmon propagation angle. These relations are demonstrated both ::: numerically and experimentally. Following we show that there is an optimal grating that can excite any surface plasmon ::: propagation angle between ±82.46 degrees and efficient polarization schemes which lead to negligible losses. Finally we ::: introduce a formalism that relates general surface plasmon beams to corresponding incident optical beams and using it ::: we demonstrate numerically a varying position surface plasmon hotspot generation.