High-current plasma lens and focusing of intense ion beams

Abstract

The static and dynamic characteristics of a high-current plasma lens (PL) with the two-component quasineutral plasma medium formed by a wide-aperture pulse periodical ion beam and secondary ion–electron emission, with the features of focusing and control of a well-formed low-divergent multiaperture ion beam by this lens are investigated experimentally in a wide energy range. It is shown that a careful selection of magnetic field geometry, the fixing electrode number, and the external potential distribution on them, according to theoretical plasmaoptics principles, allow a radial electrical profile in a volume of PL to be modified in a given way. This enables the reduction of the spherical aberration of the beam which is being focused. Experimentally and theoretically it is shown that the controlled introduction of spherical aberrations makes it possible to control a radial beam profile on a target and, in particular, to make it homogeneous. The results of low-energy metal ion beams focused and controlled by PL are obtained. Lens collective processes caused by a principally unremovable magnetic field radial gradient in the ion beam focusing direction are investigated and it is shown that lens electron leakages are connected with these turbulent noises.

Spatial and time dynamics of non-linear vortices in high-current plasma lens

“…The similar behavior of electrons was observed in experiments in purely electron plasma, in charged plasma of the lens [1,3] and in the plasma, placed in crossed radial electrical and longitudinal magnetic fields.…”

“…The charged plasma lens, intended for focussing of highcurrent ion beams, has the same crossed configuration of fields [1]. It is important to know properties of vortices at non-linear stage of their evolution.…”

Assessment of the Possibility of Modernizing a Space Charge Lens for Focusing Beams of Negative Hydrogen Ions Due to Confinement of Positive Background Ions by an Alternating Electric Field

“…However, for intense beams of positive and negative ions, magnetic lenses are used, which have significant dimensions, are heavy, and consume significant power during operation. To focus beams of positive ions, so-called plasma lenses were developed, which, with sufficiently small dimensions, effectively created electric fields suitable for the focusing [2]. As for the use of a charged plasma background for focusing beams of negative hydrogen ions, research in this direction is being conducted.…”