Propagation of an Intense Ion Beam Transverse to a Magnetic Field

Abstract

It has been verified experimentally that an intense, space-charge-neutralized ion beam having a dielectric constant $\ensuremath{\epsilon}\ensuremath{\gg}1$ will cross a transverse magnetic field undeflected. A polarization electric field $\stackrel{\ensuremath{\rightarrow}}{\mathrm{E}}$ is measured within the beam channel such that $\stackrel{\ensuremath{\rightarrow}}{\mathrm{E}}+(\frac{\stackrel{\ensuremath{\rightarrow}}{\mathrm{v}}}{c})\ifmmode\times\else\texttimes\fi{}\stackrel{\ensuremath{\rightarrow}}{\mathrm{B}}=0$, where $\stackrel{\ensuremath{\rightarrow}}{\mathrm{v}}$ is the beam velocity and $\stackrel{\ensuremath{\rightarrow}}{\mathrm{B}}$ is the applied field. It is shown theoretically that $\ensuremath{\epsilon}\ensuremath{\gg}{(\frac{{m}_{i}}{{m}_{e}})}^{\frac{1}{2}}$ is required for the beam to enter the transverse field from a region with no field, where ${m}_{i}$ and ${m}_{e}$ are the ion and electron masses.