Investigation of the Tail of a Fe Plasma Plume Passing Through Solenoidal Magnetic Field for a Laser Ion Source

To control the plasma flux of a laser ion source for a desired beam profile, we investigated the influence of a quasi-static magnetic field generated by a solenoidal coil on the tail of an Fe ablation plasma. We observed that the magnetic field converged the outer plasma and almost did not affect the inner plasma when the plasma drifted through the field region. The convergence points of the outer plasma depended on the longitudinal velocity. The results indicate that diamagnetic current was induced in the outer plasma, and therefore, the outer plasma received the converging force and the magnetic field in the inner region was excluded by the plasma intrusion. The results also mean that we have to consider the magnetic effect on the transverse distribution of plasma flux to minimize the emittance growth and obtain desirable beam optics.