CHARGE AND CURRENT NEUTRALIZATION OF AN ION BEAM PULSE BY BACKGROUND PLASMA IN THE PRESENCE OF APPLIED MAGNETIC FIELD*

Plasma can be used as a convenient medium for manipulating intense charged particle beams, e.g., for ballistic focusing and steering, because the plasma can effectively reduce the self-space charge potential and self-magnetic field of the beam pulse. We previously developed a reduced analytical model of beam charge and current neutralization for an ion beam pulse propagating in a cold background plasma. The reduced-fluid description provides an important benchmark for numerical codes and yields useful scaling relations for different beam and plasma parameters. This model has been extended to include the additional effects of an applied solenoidal magnetic field. Simulations show that the self-magnetic field structure of the ion beam pulse propagating through background plasma can be complex and non-stationary. The linear system of Maxwell’s equations for the self-electromagnetic fields can be solved analytically in Fourier space. For a strong enough applied magnetic field, poles emerge in Fourier space. These poles are an indication that whistler and low-hybrid waves can be excited by the beam pulse