Relativistic electron beam propagation in high pressure gaseous media

Intense relativistic electron beam (IREB) propagation is intrinsically unstable in high pressure gaseous media. The dominant instability is the resistive hose. The growth rate of the hose is reduced by beam conditioning which incorporates beam emittance tailoring and current centroid sweep damping. In the experiments reported in this work we conditioned the SuperIBEX IREB using combinations of an argon filled IFR and an air filled or evacuated active Bθ cell. The IFR cell provides the required radius tailoring which is converted to emittance tailoring using a titanium exit foil or by injection into the active Bθ cell. The B0 cell damps the beam centroid sweep due to the enharmonic restoring force applied by the wire's magnetic field on a sweeping IREB. These conditioning cells successfully stabilized the beam for approximately 20 betatron wavelengths (λβ) and propagation lengths exceeding 5 m. The objective of the experiments reported here is to show die effect on propagation of using the conditioning cells to vary die beam parameters including beam emittance, beam current, radius tailoring, and sweep reduction.