LLNL Compact Torus Acceleration 1995

UCRL-ID-120238 Final Report on the LLNL Compact Torus Acceleration Project J. Eddleman, J. Hammer, C Haxtman, H. Mc Lean, and A. Molvik March 19,1995 rnfv*fn*«*«ff««f*«*Mn«ft«fwvn*tfnten«**ttftivfn*«Hf«vf*f*^ •>• •>• s, * * >i. ' * 1 \ s ^ •• •> sfr M « \* <n This U an informal report intended primarily for internal or limited external distribution. Theopwonsandcor Klasionss Utedaretho Moftheaathorandmay or may not be those of the Laboratory. Work performed under the auspices of the U.S. Department of Energy by the Lawrence Iivermore National Laboratory under Contract W-7405-Eng-48. DISCLAIMER This document was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor the University 6/ California nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or the University of California. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or the University of California, and shall not be used for advertising or product endorsement purposes. This report has been reproduced directly from the best available copy. Available to DOE and DOE contractors from the Office of Scientific and Technical Information P.O. Box 62, Oak Ridge, TN 37831 Prices available from (615) 576-8401, FTS 626-8401 Available to the public from the National Technical Information Service U.S. Department of Commerce 5285 Port Royal Rd., Springfield, VA 22161 DISCLAIMER Portions of this document may be illegible in electronic image products. Images are produced from the best available original document. Final Report on the LLNL Compact Torus Acceleration Project March 19,1995 James Eddleman, James Hammer, Charles Hartman, Harry Mc Lean, and Arthur Molvik Introduction In this report, we summarize recent work at LLNL on the compact torus (CT) acceleration project. The CT accelerator is a novel technique for projecting plasmas to high velocities and reaching high energy density states. The accelerator exploits magnetic confinement in the CT to stably transport plasma over large distances and to directed kinetic energies large in comparison with the CT internal and magnetic energy. Applications range from heating and fueling magnetic fusion devices, generation of intense pulses of x-rays or neutrons for weapons effects and high energy-density fusion concepts. Beginning in 1986, we conducted experiments with the Ring Accelerator Experiment (RACE) accelerator at LLNL to establish proof-of-principal for the concept. The accelerator concept and early modeling studies are found in references 1 and 2. The first experiments on CT acceleration are described in reference 3 and experiments on slow formation and compression in references 4 and 5. Applications are discussed in references 2, and 6-8. More recent RACE experiments that demonstrated the predicted feature of magnetic flux compression during CT focusing are described in section 1 below. The last experimental series from 1992 to 1993 studied the effects of drag on the CT from wall-evolved gases and potential ways of reducing the drag through heating the electrodes. Drag effects strongly limited the operating regime in the precompressor/acceleration- focusing geometry. Recent analysis of data from these experiments shows that the drag was primarily due to snowplow of the CT through gas filling the accelerator tube. The gas was apparently produced during the formation stage of the CT. These results are reported in section 2.1. Modeling of wall plasma effects is described in