Yet another criterion for global existence in the 3D relativistic   Vlasov-Maxwell system
  We prove that solutions of the 3D relativistic Vlasov-Maxwell system can be extended, as long as the quantity $\sigma_{-1}(t, x) = \max_{|\omega|=1} \,\int_{R^3} \frac{dp}{\sqrt{1+p^2}}\, \frac{1}{(1+v\cdot\omega)}\, f(t, x, p)$ is bounded in $L^2_x$. 
Markus Kunze
math.AP math-ph math.MP