Cross field injection and trapping of a continuous plasma beam in a magnetic mirror

Abstract

A beam of potassium plasma of 1012 cm-3 density from a continuous magnetoplasma-dynamic arc source has been propagated into a magnetic mirror device in a direction transverse to the magnetic field. A self induced polarization and E*B drift of the beam was observed. The plasma filled the magnetic mirror to a density of 1012 cm-3 when insulating end plugs were used. The density was slightly reduced if the mirror ratio was reduced to unity and was reduced to 1011 cm-3 if the end plugs were made conducting thus shorting the electric field. The temperature of the trapped plasma corresponded to approximately two thirds of the energy in the initial motion of the beam. These results are discussed qualitatively in terms of the polarization drift model of Schmidt (1960). The possible application of this injection technique to tandem mirrors is discussed briefly.