1,388 research outputs found
A study to determine an efficient data format and data system for a lightweight deep space probe
Design of spacebore central data system for solar probe
Controlling quasiparticle excitations in a trapped Bose-Einstein condensate
We describe an approach to quantum control of the quasiparticle excitations
in a trapped Bose-Einstein condensate based on adiabatic and diabatic changes
in the trap anisotropy. We describe our approach in the context of Landau-Zener
transition at the avoided crossings in the quasiparticle excitation spectrum.
We show that there can be population oscillation between different modes at the
specific aspect ratios of the trapping potential at which the mode energies are
almost degenerate. These effects may have implications in the expansion of an
excited condensate as well as the dynamics of a moving condensate in an atomic
wave guide with a varying width
Atmospheric frontal zone studies
The research supported by this contract and directed Activities in the inversion and interpretation of data produced by the Nimbus-7 scanning multichannel microwave radiometer (SMMR) are reported. There were five principal subjects: (1) modeling of the emissivity of foam patches on the ocean surface; (2) inversion of radiometric data by a multidimensional algorithm; (3) an operational water vapor retrieval algorithm; (4) inference of Antarctic firm accumulation rates; and (5) inference of water vapor over the Arctic sea ice
Photon lifetime in a cavity containing a slow-light medium
We investigate experimentally the lifetime of the photons in a cavity
containing a medium exhibiting strong positive dispersion. This intracavity
positive dispersion is provided by a metastable helium gas at room temperature
in the electromagnetically induced transparency (EIT) regime, in which light
propagates at a group velocity of the order of 10000 m/s. The results
definitely prove that the lifetime of the cavity photons is governed by the
group velocity of light in the cavity, and not its phase velocity.Comment: Accepted for publication in Optics Letter
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The technology of ICRF systems
The technology of ICRF systems has made substantial gains in the past few years. The total power levels have increased from the 5-MW level to greater than 20 MW; the pulse lengths have increased from the 100-msec level to 30 seconds. Recently, fast wave current drive (FWCD) has been demonstrated using phased arrays of ICRF antennas. In order to achieve such large gains, substantial changes and improvements were needed in the level of design analysis, fabrication techniques, and system controls
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