Superfilamentation in air
  The interaction between a large number of laser filaments brought together using weak external focusing leads to the emergence of few filamentary structures reminiscent of standard filaments, but carrying a higher intensity. The resulting plasma is measured to be one order of magnitude denser than for short-scale filaments. This new propagation regime is dubbed superfilamentation. Numerical simulations of a nonlinear envelope equation provide good agreement with experiments. 
Guillaume Point, Yohann Brelet, Aur\'elien Houard, Vytautas Jukna,   Carles Mili\'an, J\'er\^ome Carbonnel, Yi Liu, Arnaud C...
physics.optics physics.plasm-ph