Studies of an unneutral electron cloud confined in a multiple-mirrored toroidal magnetic fielda)

An unneutral electron cloud of 3×1013 electrons with a number density of 1011 cm−3 was compressed and confined by a multiple-mirrored toroidal magnetic field. The radial electric field associated with this electron cloud was about 105 V/cm. The electrons, having a large magnetic moment, were confined by the magnetic mirrors. An upper limit of 1 A was set on the induced current when a toroidal electric field of 10 V/cm was applied. This puts a limit n<4×108 cm−1 on the line density of electrons with perpendicular energy lower than 300 eV.