How really transverse filamentation is?
2007 - A Bret, L. Gremillet, J.C. Bellido
Physics of Plasmas 14, 032103 (2007)
Abtract
It is generally considered that the linear filamentation instability encountered when two counter streaming electron beams interpenetrate is purely transverse. Exact and approximated results are derived in the relativistic fluid approximation showing that within some parameter range, filamentation can be indeed almost longitudinal with cos(k,Eˆ)?1?3.1/?b, where ?b is the relativistic factor of the beam.Temperatureeffects are then evaluated through relativistic kinetic theory and yield even fewer transverse filamentation modes. In the cold case, the transverse approximation overestimates the growth rate by a factor ??b???.