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Title: Status of 2XIIB plasma confinement experiments

Abstract

This report describes the status of 2XIIB neutral beam injection experiments with stabilizing plasma. The stream suppresses ion-cyclotron fluctuations and permits density to 5 x 10$sup 13$ cm$sup -3$. The ion energy is 13 keV, and electron temperature reaches 140 eV. Plasma confinement increases with ion energy and n tau reaches 7 x 10$sup 10$ cm$sup -3$.s at 13 keV. The n tau energy scaling is consistent with electron drag and ion-ion scattering losses. Buildup on a streaming plasma in a steady-state magnetic field is described. (auth)

Authors:
; ;
Publication Date:
Research Org.:
California Univ., Livermore (USA). Lawrence Livermore Lab.
Sponsoring Org.:
US Energy Research and Development Administration (ERDA)
OSTI Identifier:
4096558
Report Number(s):
UCID-17037
NSA Number:
NSA-33-019804
DOE Contract Number:
W-7405-ENG-48
Resource Type:
Technical Report
Resource Relation:
Other Information: Orig. Receipt Date: 30-JUN-76
Country of Publication:
United States
Language:
English
Subject:
N70100* -Physics-Controlled Thermonuclear Research- Confinement &; Heating; 700101* -Fusion Energy-Plasma Research-Plasma Confinement &; *2X DEVICES- PLASMA CONFINEMENT; CYCLOTRON FREQUENCY; IONS; MAGNETIC FIELDS; PLASMA DENSITY

Citation Formats

Coensgen, F. J., Clauser, J. F., and Correll, D. L. Status of 2XIIB plasma confinement experiments. United States: N. p., 1976. Web. doi:10.2172/4096558.
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Coensgen, F. J., Clauser, J. F., & Correll, D. L. Status of 2XIIB plasma confinement experiments. United States. doi:10.2172/4096558.
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Coensgen, F. J., Clauser, J. F., and Correll, D. L. Wed . "Status of 2XIIB plasma confinement experiments". United States. doi:10.2172/4096558. https://www.osti.gov/servlets/purl/4096558.
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@article{osti_4096558,
title = {Status of 2XIIB plasma confinement experiments},
author = {Coensgen, F. J. and Clauser, J. F. and Correll, D. L.},
abstractNote = {This report describes the status of 2XIIB neutral beam injection experiments with stabilizing plasma. The stream suppresses ion-cyclotron fluctuations and permits density to 5 x 10$sup 13$ cm$sup -3$. The ion energy is 13 keV, and electron temperature reaches 140 eV. Plasma confinement increases with ion energy and n tau reaches 7 x 10$sup 10$ cm$sup -3$.s at 13 keV. The n tau energy scaling is consistent with electron drag and ion-ion scattering losses. Buildup on a streaming plasma in a steady-state magnetic field is described. (auth)},
doi = {10.2172/4096558},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Feb 11 00:00:00 EST 1976},
month = {Wed Feb 11 00:00:00 EST 1976}
}
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Technical Report:
View Technical Report (4.00 MB)
DOI:  10.2172/4096558
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  • ; ;
    This paper discusses results of plasma-confinement experiments in the 2XIIB magnetic mirror device. We report experiments attempting to achieve field-reversal using neutral-beam injection in which the central magnetic field is reduced by 90% but field lines are not closed. Experiments with different neutral-beam aiming show that at constant beta both electron temperature and the energy-confinement parameter (n tau) increase at larger radius. Finally, we discuss recent improvements in electron temperature and microinstability measurements.

  • ; ;
    This paper reports results of 2XIIB neutral-beam injection experiments with plasma-stream stabilization. The plasma stream is provided either by a pulsed plasma generator located on the field lines outside the plasma region or by ionization of neutral gas introduced at the mirror throat. In the latter case, the gas is ionized by the normal particle flux through the magnetic mirror. A method of plasma startup and sustenance in a steady-state magnetic field is reported in which the plasma generator serves as the initial target for the neutral beams. After an energetic plasma of sufficient density is established, the plasma generatormore » stream is replaced by the gas-fed stream. Lifetimes of the stabilized plasma increase with plasma temperature in agreement with the plasma stabilization of the drift-cyclotron loss-cone mode. The following plasma parameters are attained using the pulsed plasma generator for stabilization: n approximately equal to 5 x 10/sup 13/ cm/sup -3/, W/sub i/ approximately equal to 13 keV, T/sub e/ = 85 eV, and n tau/sub p/ approximately equal to 7 x 10/sup 10/ cm/sup -3/ . s. With the gas feed, the mean deuterium ion energy is 9 keV and the peak density n approximately equal to 10/sup 14/ cm/sup -3/. In the latter case, the energy confinement parameter reaches n tau/sub E/ = 6.2 x 10/sup 10/ cm/sup -3/ . s, and the particle confinement parameter reaches n tau/sub p/ = 1.2 x 10/sup 11/ cm/sup -3/ . s.« less

  • ; ;
    This paper reports results of 2XIIB neutral-beam injection experiments with plasma-stream stabilization. The plasma stream is provided either by a pulsed plasma generator located on the field lines outside the plasma region or by ionization of neutral gas introduced at the mirror throat. In the latter case, the gas is ionized by the normal particle flux through the magnetic mirror. A method of plasma startup and sustenance in a steady-state magnetic field is reported in which the plasma stream from the pulsed plasma generator serves as the initial target for the neutral beams. After an energetic plasma of sufficient densitymore » is established, the plasma generator stream is replaced by the gas-fed stream. Lifetimes of the stabilized plasma increase with plasma temperature in agreement with the plasma stabilization of the drift-cyclotron loss-cone mode. The following plasma parameters are attained using the pulsed plasma generator for stabilization: n approximately 5 x 10/sup 13/ cm/sup -3/, anti W/sub i/ approximately 13 keV, T/sub e/ = 140 eV, and ntau/sub p/ approximately 7 x 10/sup 10/ cm/sup -3/.s. With the gas feed, the mean deuterium ion energy is 9 keV and the peak density n approximately 10/sup 14/ cm/sup -3/. In the latter case, the energy confinement parameter reaches ntau/sub E/ = 7 x 10/sup 10/ cm/sup -3/.s, and the particle confinement parameter reaches ntau/sub p/ = 1 x 10/sup 11/ cm/sup -3/.s.« less

  • ; ;
    Preliminary results are presented of a study of cross-field plasma injection in the 2XIIB mirror machine. Plasma accelerated by a coaxial deflagration gun was observed to pass 3.5M across the vacuum field, and some trapping was observed when the gun plasma intersected a plasma streaming along B at the center of the magnetic well. Parameters for the experiment are: gun plasma kinetic energy 50 to 200 eV, n/sub gun/ = 3 x 10/sup 13/ cm/sup -3/, streaming plasma 25 to 50 eV and n/sub streaming/ = 6 x 10/sup 11/ cm/sup -3/, duration of both 100 to 200 ..mu..sec. Formore » the trapped plasma, n = 2.4 x 10/sup 12/ cm/sup -3/, and the decay time is t/sub /sup 1///sub 2// = 400 ..mu..sec consistent with Coulomb scattering loss at 100 eV mean ion energy.« less