  Electron beam (e-beam) generated plasmas with applied crossed electric and
magnetic $\left(\mathbf{E} \times \mathbf{B}\right)$ fields are promising for
low damage processing of materials with applications to microelectronics and
quantum information systems. In cylindrical e-beam $\mathbf{E} \times
\mathbf{B}$ plasmas, radial confinement of electrons and ions is achieved by an
axial magnetic field and radial electric field, respectively. To control the
axial confinement of electrons, such e-beam generated plasma sources may
incorporate a conducting boundary known as an anticathode, which is placed on
the axially opposite side of the plasma from the cathode. In this work, it is
shown that varying the anticathode voltage bias can control the degree to which
the anticathode collects or repels incident electrons, allowing control of warm
electron (electron energies in 10-30 eV range) and beam electron population
confinement. It is suggested that the effect of the anticathode bias on the
formation of these distinct electron populations is also associated with the
transition between weak turbulence and strong Langmuir turbulence.
