Toy model of the "fountain effect" for magnetic field generation in   intense laser-solid interactions
  A very simple "geometrical" model of a fountain is analyzed to evaluate the net flow on the ground resulting from the superposition of the source and the falling streams. On this basis we suggest a scaling for the magnetic field generated at the rear surface of high-intensity laser-irradiated solid targets due to the "fountain effect" related to fast electrons escaping in vacuum. 
Andrea Macchi
physics.plasm-ph