Sweeping the plasma before it, the interplanetary magnetic field quickly penetrated into an initially diamagnetic barium plasma cloud. The field was strongly compressed and extended in the flow direction. Ions accelerated by electric polarization fields formed a visible tail at the rear of the cloud; their recoil balancing the magnetic stresses. The dominant lateral motion of the head of the artificial comet is attributed to a recoil of ions extracted by the interplanetary electric field.