33,980 research outputs found
Isotope separation using metallic vapor lasers
The isotope U235 is separated from a gasified isotope mixture of U235 and U238 by selectively exciting the former from the ground state utilizing resonant absorption of radiation from precisely tuned lasers. The excited isotope is then selectively ionized by electron bombardment. It then is separated from the remaining isotope mixture by electromagnetic separation
Double-discharge copper-vapor laser
Power supply for discharge pulses consists of two capacitors that are made to discharge synchronously with adjustable time intervals. First pulse is switched with hydrogen thyratron, and second by spark gap. Lasing action peaks for appropriate combination of these two parameters
Three-dimensional modeling of lightning-induced electromagnetic pulses on Venus, Jupiter and Saturn
While lightning activity in Venus is still controversial, its existence in
Jupiter and Saturn was first detected by the Voyager missions and later on
confirmed by Cassini and New Horizons optical recordings in the case of
Jupiter, and recently by Cassini on Saturn in 2009. Based on a recently
developed 3D model we investigate the influence of lightning-emitted
electromagnetic pulses (EMP) on the upper atmosphere of Venus, Saturn and
Jupiter. We explore how different lightning properties such as total energy
released and orientation (vertical, horizontal, oblique) can produce
mesospheric transient optical emissions of different shapes, sizes and
intensities. Moreover, we show that the relatively strong background magnetic
field of Saturn can enhance the lightning-induced quasi-electrostatic and
inductive electric field components above 1000 km of altitude producing
stronger transient optical emissions that could be detected from orbital
probes
Initial POLAR MFE observation of substorm signatures in the polar magnetosphere
This paper studies substorm influences in the polar magnetosphere using data from the POLAR magnetic field experiment (MFE). The POLAR spacecraft remains in the high altitude polar magnetosphere for extended periods around apogee. There it can stay at nearly constant altitude through all phases of a substorm, which was not possible on previous missions. We report such an event on March 28, 1996. Ground magnetometers monitored substorm activity, while the POLAR spacecraft, directly over the pole at (−0.8, −0.6, 8.5) RE in GSM coordinates, observed a corresponding perturbation in the total magnetic field strength. The total magnetic field first increased, then recovered toward quiet levels, consistent with erosion of magnetic flux from the dayside magnetosphere, followed by transport of that flux to the magnetotail, and eventual onset of tail reconnection and the return of that magnetic flux to the dayside magnetosphere
Fiber optic control system integration
A total fiber optic, integrated propulsion/flight control system concept for advanced fighter aircraft is presented. Fiber optic technology pertaining to this system is identified and evaluated for application readiness. A fiber optic sensor vendor survey was completed, and the results are reported. The advantages of centralized/direct architecture are reviewed, and the concept of the protocol branch is explained. Preliminary protocol branch selections are made based on the F-18/F404 application. Concepts for new optical tools are described. Development plans for the optical technology and the described system are included
On inward motion of the magnetopause preceding a substorm
Magnetopause inward motion preceding magnetic storms observed by means of OGO-E magnetomete
Apollo particles and fields subsatellite magnetometer experiment
The results of the Apollo 15 subsatellite magnetometer experiment are reported. The magnetometer is described including the operation, and specifications. Orbit plots presented are altitude versus time, selenographic longitude versus latitude, and the ecliptic projection of the earth-moon system. The lunar magnetic field, solar wind interaction with the moon, the transfer function of the moon, and the plasma sheet interaction with the moon are discussed
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p-Wave stabilization of three-dimensional Bose-Fermi solitons
We explore bright soliton solutions of ultracold Bose-Fermi gases, showing
that the presence of p-wave interactions can remove the usual collapse
instability and support stable soliton solutions that are global energy minima.
A variational model that incorporates the relevant s- and p-wave interactions
in the system is established analytically and solved numerically to probe the
dependencies of the solitons on key experimental parameters. Under attractive
s-wave interactions, bright solitons exist only as meta-stable states
susceptible to collapse. Remarkably, the presence of repulsive p-wave
interactions alleviates this collapse instability. This dramatically widens the
range of experimentally-achievable soliton solutions and indicates greatly
enhanced robustness. While we focus specifically on the boson-fermion pairing
of 87Rb and 40K, the stabilization inferred by repulsive p-wave interactions
should apply to the wider remit of ultracold Bose-Fermi mixtures.Comment: 9 pages, 6 figure
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