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论文类型：期刊论文

发表时间：2016-12-01

发表刊物：PHYSICS OF PLASMAS

收录刊物：SCIE、EI、Scopus

卷号：23

期号：12

ISSN号：1070-664X

摘要：The focused high-intensity pulsed ion beam (HIPIB) of 100 ns order pulse is generated with respect to its spatial stability in two types of magnetically insulated ion diodes (MIDs) with geometrical focusing configuration using the passive anode, i.e., insulation of electrons with an external magnetic-field and a self-magnetic field, respectively. Anode plasma formation for the ion beam generation is based on different processes in the two types of MIDs, as the surface breakdown on the polymer-coated anode operated in the unipolar pulse mode for the external-magnetic field MID and the explosive electron emission on the graphite anode in the bipolar-pulse mode for the self-magnetic field MID. Typical energy density per pulse is in the range of 3-6 J/cm(2), at an accelerating voltage of 200-300 kV with a pulse duration of 120-150 ns. The spatial deviations of the HIPIB is evaluated by measuring the energy density distribution by using an infrared diagnostic method considering neutralizing during the ion beam propagation to the focal plane with a spatial resolution of 1 mm. The ion beam deviation is about +/- 1.5mm for the external-magnetic field MID and +/- 2.5mm for the self-magnetic field MID, leading to a fluctuation in the energy density of 1%-12%, and 9%-27% within a 10mm range at the focal point, respectively. It is revealed that the displacement of different parts of a beam spot occurs nonsynchronously, mainly attributable to the intrinsic diode processes of plasma generation and expansion, and ion beam extraction from the anode-cathode gap, while the influence of magnetic field in the transportation region is negligible. The ion beam spatial deviation has a major influence on the shot-to-shot stability of ion beam, and it is suggested that the stability can be enhanced via diode process improvement. Published by AIP Publishing.