Axial and Radial Compression of Ion Beams.
Final rept. 15 Jan 79-26 Feb 80,
JAYCOR ALEXANDRIA VA
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The present report concentrates on the physics of propagating intense ion beams in plasma channels. In particular, the theoretical aspects are studied of the possible effects during ion beam transport on the structure of electromagnetic fields in the plasma. The ion orbits were solved for different classes of plasma channels including bumpy ones in order to evaluate the sensitivity of beam losses due to channels that deviate from idealistic shapes. The consideration of different plasma instabilities, the hydrodynamic motion of the plasma, propagation in filamentary channels and beam energy losses put realistic limits on how much ion current can be propagated using the simple steady plasma channel concept. Axial bunching of the beam via time dependent voltage ramping of the ion diode was analyzed and found to be sound concept as long as no more than an order of magnitude pulse compression is attempted. The radial compression is viable on a small scale in tapered channels giving a factor of 2 increase in current density and on a large scale if self magnetic fields fully penetrate the media giving rise to an order of magnitude increase in ion beam current density. Further theoretical investigation on the details of the above mechanisms are presently in progress including new plasma channel schemes that help to push upwards the limits on the ion currents.
- Nuclear Physics and Elementary Particle Physics