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

Technical Report · Thu Mar 01 00:00:00 EST 1962

OSTI ID:4792878

; 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

• Research Organization: Los Alamos Scientific Lab., N. Mex.
• DOE Contract Number: W-7405-ENG-36
• NSA Number: NSA-16-015719
• OSTI ID: 4792878
• Report Number(s): LAMS-2682
• Resource Relation: Other Information: Orig. Receipt Date: 31-DEC-62
• Country of Publication: United States
• Language: English

Related Subjects

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