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Effect of time-of-flight bunching on efficiency of light-ion-beam inertial-confinement-fusion transport schemes

Journal Article · · Journal of Applied Physics; (United States)
DOI:https://doi.org/10.1063/1.355984· OSTI ID:5000077
 [1];  [2];  [3]
  1. Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States)
  2. JAYCOR, Inc., Vienna, Virginia 22182 (United States)
  3. Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)

The Laboratory Microfusion Facility (LMF) has been proposed for the study of high-gain, high-yield inertial-confinement-fusion targets. The light-ion LMF approach uses a multimodular system with applied-[ital B] extraction diodes as ion sources. A number of ion-beam transport and focusing schemes are being considered to deliver the beams from the diodes to the target. These include ballistic transport with solenoidal lens focusing, [ital z]-discharge channel transport, and wire-guided transport. The energy transport efficiency [eta][sub [ital t]] has been defined and calculated as a function of various system parameters so that point designs can be developed for each scheme. The analysis takes into account target requirements and realistic constraints on diode operation, beam transport, and packing. The effect on [eta][sub [ital t]] of voltage ramping for time-of-flight beam bunching during transport is considered here. Although only 5 mrad microdivergence calculations are presented here, results for bunching factors of [le]3 show that transport efficiencies of [gt]50% can be obtained for all three systems within a range of system parameters which seem achievable (i.e., for diode microdivergence within 5--10 mrad, for diode radius within 10--15 cm, and for diode-ion-current density within 2--10 kA/cm[sup 2]). In particular, the point design for the baseline LMF system using ballistic transport with solenoidal lens focusing and a bunching factor of 2 was calculated to have [eta][sub [ital t]]=84%. Other factors affecting the overall system efficiency, but not included in the analysis, are also identified and estimated.

OSTI ID:
5000077
Journal Information:
Journal of Applied Physics; (United States), Journal Name: Journal of Applied Physics; (United States) Vol. 75:9; ISSN JAPIAU; ISSN 0021-8979
Country of Publication:
United States
Language:
English