skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: QUARTERLY STATUS REPORT OF THE LASL CONTROLLED THERMONUCLEAR RESEARCH PROGRAM FOR PERIOD ENDING FEBRUARY 20, 1962

Abstract

; 9 < : = > ; ; = 7 > < 9 : 7 8 9 $ ard reproducing the long containmert times for energetic deuterons observed in the Baked Picket Fence experiment. The first attempts showed no evidence for containment with the coils connected for simple picket fence operation. Using a redesigned gun, containment of energetic deuterons was immediately observed. Typical containment times are about 10 msec. This result indicates that there is an apparent threshold for trapping which depends in some way on the number density of the injected plasma. Mark II Baked Picket Fence. Experiments to locate the source of neutron production and to determine the dimensions of the plasma volume have continued. Confinement times of up to 350 mu sec for this apparatus appear to exceed theoretical predictions by a factor of about 10. This is due to thc relatively large size of the nonadiabatic region for deuteron energies >10 kev which are measured leaking out of the ring cusp. A preliminary model was suggested in which the primary mechanism of ion confinement is due to the adiabatic trapping of electrons. These trapped electrons create a negative potential well which holds the ions. The ionmore » loss rate is then brought into equilibrium with the nonadiabatic loss rate of the electrons. Coaxial Gun Research. A study of the characteristics of a coaxial gun when operated in the mode to accelerate deuterons to relatively high energies (>5 kev) is under way. Changes in the geometry of the electrodes were made. Optimum operation to date when evaluated in terms of total neutron yield and calorimetric measurements was obtained with an inner electrode 6.2 cm diameter and 1.5 to 3.8 cm long and an outer electrode 10 cm diameter and length 37.5 cm. The lengths of electrodes are measured from the gas ports. Resonant Helix- Coaxial Gun Injection Experiment. Investigation of the interaction of a resonant helix on the plasma produced by a coaxial gun was continued. The results show that the helix increases the diamagnetism of a plasma passing through it, and a mirror placed beyond the helix produces a longer diamagnetic signal upstream from the mirror, indicating some plasma reflection. Particle detectors also verify that some plasma is reflected from this mirror. Experiments using two mirrors, one at each end of the helix, in an attempt to trap plasma between them, have not shown appreciable plasma containment. Cyclotron Radiation Maser. A theoretical study was carried out on the dependence of negative absorption on the nature of the electron velocity distribution. Results obtained for 90 deg propagation with respect to the magnetic field include observations that negative absorption, ( alpha ), depends upon the existence of a peak away from zero velocity, the magnitude of ( alpha ) depends upon the maximum positive slope of the distribution function, and angular distribution of electrons is not very important provided a positive slope exists in the distribution function vs velocity perpendicular to magnetic field. It was also found that transit time broadening due to motion along magnetic lines across the microwave system leads to reduced values for ( alpha ) and magnetic field inhomogeneities lead to a net reduction of ( alpha ) for a given maser volume. Injected Scylla III. Plans are being made to extend the experiments with gun plasma injection of Scylla III and to measure the energies of the deuterons trapped and compressed in the fast mirror field. It is proposed to apply a method in which plasma will be spilled out of the compression region through a quasi d-c mirror on the far side from the gun. After spilling through the mirror, the plasma will pass through an axial field which decreases with distance gradually enough to be nearly adiabatic. This should transform the predominantly transverse energy of the ions after compression mostly into axial energy and deliver a large fraction of the plasma into a long drift space for measuring ion energy distributions. The drift space will be provided with« less

Publication Date:
Research Org.:
Los Alamos Scientific Lab., N. Mex.
OSTI Identifier:
4792878
Report Number(s):
LAMS-2682
NSA Number:
NSA-16-015719
DOE Contract Number:  
W-7405-ENG-36
Resource Type:
Technical Report
Resource Relation:
Other Information: Orig. Receipt Date: 31-DEC-62
Country of Publication:
United States
Language:
English
Subject:
PHYSICS; ABSORPTION; ACCELERATORS; ANGULAR DISTRIBUTION; CALORIMETERS; CAPACITORS; CIRCUITS; COILS; CONFIGURATION; CONFINEMENT; CONTAINMENT TIME; CUSPED GEOMETRIES; CYCLOTRON RADIATION; DENSITY; DEUTERON BEAMS; DEUTERONS; DIAMAGNETISM; DIELECTRICS; DISTRIBUTION; EFFICIENCY; ELECTRIC ARCS; ELECTRIC DISCHARGES; ELECTRIC POTENTIAL; ELECTRODES; ELECTRONS; ENERGY; ENERGY RANGE; FABRICATION; FLUTE INSTABILITY; FREQUENCY; INDUCTION; INJECTION; INSTRUMENTS; INTERACTIONS; IONS; KEV RANGE; LOSSES; MAGNETIC COMPRESSION; MAGNETIC FIELDS; MAGNETIC MIRRORS; MAGNETISM; MASERS; MEASURED VALUES; MICROWAVES; MOTION; NEUTRONS; OPENINGS; OPERATION; PARTICLE SOURCES; PERF

Citation Formats

. QUARTERLY STATUS REPORT OF THE LASL CONTROLLED THERMONUCLEAR RESEARCH PROGRAM FOR PERIOD ENDING FEBRUARY 20, 1962. United States: N. p., 1962. Web.
. QUARTERLY STATUS REPORT OF THE LASL CONTROLLED THERMONUCLEAR RESEARCH PROGRAM FOR PERIOD ENDING FEBRUARY 20, 1962. United States.
. Thu . "QUARTERLY STATUS REPORT OF THE LASL CONTROLLED THERMONUCLEAR RESEARCH PROGRAM FOR PERIOD ENDING FEBRUARY 20, 1962". United States.
@article{osti_4792878,
title = {QUARTERLY STATUS REPORT OF THE LASL CONTROLLED THERMONUCLEAR RESEARCH PROGRAM FOR PERIOD ENDING FEBRUARY 20, 1962},
author = {},
abstractNote = {; 9 < : = > ; ; = 7 > < 9 : 7 8 9 $ ard reproducing the long containmert times for energetic deuterons observed in the Baked Picket Fence experiment. The first attempts showed no evidence for containment with the coils connected for simple picket fence operation. Using a redesigned gun, containment of energetic deuterons was immediately observed. Typical containment times are about 10 msec. This result indicates that there is an apparent threshold for trapping which depends in some way on the number density of the injected plasma. Mark II Baked Picket Fence. Experiments to locate the source of neutron production and to determine the dimensions of the plasma volume have continued. Confinement times of up to 350 mu sec for this apparatus appear to exceed theoretical predictions by a factor of about 10. This is due to thc relatively large size of the nonadiabatic region for deuteron energies >10 kev which are measured leaking out of the ring cusp. A preliminary model was suggested in which the primary mechanism of ion confinement is due to the adiabatic trapping of electrons. These trapped electrons create a negative potential well which holds the ions. The ion loss rate is then brought into equilibrium with the nonadiabatic loss rate of the electrons. Coaxial Gun Research. A study of the characteristics of a coaxial gun when operated in the mode to accelerate deuterons to relatively high energies (>5 kev) is under way. Changes in the geometry of the electrodes were made. Optimum operation to date when evaluated in terms of total neutron yield and calorimetric measurements was obtained with an inner electrode 6.2 cm diameter and 1.5 to 3.8 cm long and an outer electrode 10 cm diameter and length 37.5 cm. The lengths of electrodes are measured from the gas ports. Resonant Helix- Coaxial Gun Injection Experiment. Investigation of the interaction of a resonant helix on the plasma produced by a coaxial gun was continued. The results show that the helix increases the diamagnetism of a plasma passing through it, and a mirror placed beyond the helix produces a longer diamagnetic signal upstream from the mirror, indicating some plasma reflection. Particle detectors also verify that some plasma is reflected from this mirror. Experiments using two mirrors, one at each end of the helix, in an attempt to trap plasma between them, have not shown appreciable plasma containment. Cyclotron Radiation Maser. A theoretical study was carried out on the dependence of negative absorption on the nature of the electron velocity distribution. Results obtained for 90 deg propagation with respect to the magnetic field include observations that negative absorption, ( alpha ), depends upon the existence of a peak away from zero velocity, the magnitude of ( alpha ) depends upon the maximum positive slope of the distribution function, and angular distribution of electrons is not very important provided a positive slope exists in the distribution function vs velocity perpendicular to magnetic field. It was also found that transit time broadening due to motion along magnetic lines across the microwave system leads to reduced values for ( alpha ) and magnetic field inhomogeneities lead to a net reduction of ( alpha ) for a given maser volume. Injected Scylla III. Plans are being made to extend the experiments with gun plasma injection of Scylla III and to measure the energies of the deuterons trapped and compressed in the fast mirror field. It is proposed to apply a method in which plasma will be spilled out of the compression region through a quasi d-c mirror on the far side from the gun. After spilling through the mirror, the plasma will pass through an axial field which decreases with distance gradually enough to be nearly adiabatic. This should transform the predominantly transverse energy of the ions after compression mostly into axial energy and deliver a large fraction of the plasma into a long drift space for measuring ion energy distributions. The drift space will be provided with},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1962},
month = {3}
}

Technical Report:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that may hold this item. Keep in mind that many technical reports are not cataloged in WorldCat.

Save / Share: