SUBROUTINE stepon
!
!   Advance one time step
!
  USE basic
  USE constants
  USE fields
  USE beam
  USE maxwellsource

  INTEGER:: i

! The particles are injected by the source
  IF (nlmaxwellsource) CALL maxwellsource_inject(time)

  DO i=1,nbspecies
  ! Boundary conditions for plasma particles outside the plasam region
    CALL bound(partslist(i))

  ! Localisation of particles in cells
    CALL localisation(partslist(i))

  ! Assemble right hand side
    CALL rhscon(partslist(i))
  END DO
! Solve Poisson equation 
  CALL poisson

  DO i=1,nbspecies
  ! Compute the electric field at the particle position
    CALL EFieldscompatparts(partslist(i))

  ! Solve Newton eq. and advance velocity by delta t
    CALL comp_velocity(partslist(i))

  ! Calculate new positions of particles
    CALL push(partslist(i))
  END DO  
! Calculate main physical quantities
  CALL diagnostics

END SUBROUTINE stepon