Status of experiments leading to a small recirculator

Abstract

A heavy ion linear induction accelerator is considered to be the leading driver candidate for an Inertial Fusion Energy reactor. To deliver a space-charge-dominated beam at the appropriate energy (several GeV), such an accelerator would be several kilometers in length. Since total length has a strong influence on accelerator cost, we are considering the potential advantages and practical implementation of a recirculating induction accelerator. To address the critical scientific and technical challenges of a recirculating space-chargedominated heavy ion beam, we have begun to develop the elements of a scaled "small recirculator". An operating recirculator must demonstrate full beam control including multi-lap operation, beam insertion/extraction, acceleration and pulse compression. At present, experiments have been conducted using a 2mA, 80keV Kf beam transported through a 45" bend; experiments on a 90" bend with five induction modulators will begin soon. This paper briefly summarizes the recirculator specifications and operational features and reports the latest experimental data as well as the developmental status of beam diagnostics.

Research and development toward heavy ion driven inertial fusion energy

“…This was measured and modeled with and without the neutralization of the beam space charge with electron distributions in the scaled final focusing experiment [17], neutralized transport experiment [18], and with simultaneous longitudinal compression of the beam in the neutralized drift compression experiment (NDCX) [19,20]. (e) Experiments on bending and studying high spacecharge beams in circular machines are being explored with electrons at the University of Maryland Electron Ring (UMER) [21][22][23] and were studied with heavy ions in the recirculator experiment [24,25]. (f) Current amplification by longitudinal compression of a few to % 50 times has been demonstrated.…”

“…Particle-in-cell (PIC) codes for beam and beam-plasma interaction have both guided and been validated by comparison to the above experiments [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. Computational tools were developed for the self-consistent modeling of the beams (and plasma if present) subject to the externally applied focusing field, acceleration field, self-field of the beam, as well as the fields from induced image-charge and currents.…”