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NASA NTRS1990

A device for introducing helical perturbations into a trailing line vortex

A perturbation generator has been designed which can be attached to the centerbody of a matched airfoil type vortex generator. The device was desired to enable the introduction of helical-wave, velocity perturbations into a vortex core to permit experimental verification of theoretical vortex stability predictions. Evaluation of the perturbation generator performance, prior to vortex stability studies, has been reported here. Controlled perturbations with frequencies above 200 hz have been produced, but visual observations were insufficient to confirm their helical character. Hot wire velocity spectrum data have confirmed the device's ability to introduce controlled frequency fluctuations. In addition, other flow oscillations have been discussed which can influence the controllability of vortex perturbations.

Ash, Robert L.↗

NASA NTRS1991

Far infrared all-sky survey

An all-sky survey at submillimeter waves is examined. Far-infrared all-sky surveys were performed using high-thoroughput bolometric detectors from a one-meter balloon telescope. Based on the large-bodied experience obtained with the original all-sky survey telescope, a number of radically different approaches were implemented. Continued balloon measurements of the spectrum of the cosmic microwave background were performed.

Richards, Paul L.↗

NASA NTRS1992

Relationship between wave energy and free energy from pickup ions in the Comet Halley environment

The free energy available from the implanted heavy ion population at Comet Halley is calculated by assuming that the initial unstable velocity space ring distribution of the ions evolves toward a bispherical shell. Ultimately this free energy adds to the turbulence in the solar wind. Upstream and downstream free energies are obtained separately for the conditions observed along the Giotto spacecraft trajectory. The results indicate that the waves are mostly upstream propagating in the solar wind frame. The total free energy density always exceeds the measured wave energy density because, as expected in the nonlinear process of ion scattering, the available energy is not all immediately released. An estimate of the amount which has been released can be obtained from the measured oxygen ion distributions and again it exceeds that observed. The theoretical analysis is extended to calculate the k spectrum of the cometary-ion-generated turbulence.

Huddleston, D. E.↗

NASA NTRS1993

Observation of 3-6 day meridional wind oscillations over the tropical Pacific, 1973-1992: Vertical structure and interannual variability

Rawinsonde data from tropical Pacific stations were examined for westward-propagating 3-6-day meridional wind oscillations in the troposphere and lower stratosphere, 1973-1992. Four types were identified from cross-spectrum and principal component analysis. (1) The dominant oscillation, near 250 mb, had a period slightly greater than 5 days, zonal wavenumber 4-6, and modified Rossby-gravity structure near the date line. (2) In the western Pacific lower troposphere there was broadband activity with short zonal scale, coupled to upper-tropospheric waves in NH summer. (3) In the central Pacific, during NH autumn, there was a well-defined approximately 4 1/2-day oscillation with maximum amplitude in the lower troposphere and baroclinic phase tilt above. The vertical structure suggested coupling to deep tropical convection; this interpretation was supported by correlation of meridional wind with antisymmetric outgoing longwave radiation. (4) In the stratosphere, Rossby-gravity waves had periods less than or equal to 4 days and zonal wavenumber 3-4. Unlike tropospheric waves, these disturbances were coherent in a shallow layer, largest in west phase of quasi-biennial oscillation (QBO) and annual cycle (NH winter-spring).

Dunkerton, Timothy J.↗

NASA NTRS1996

A study of dusty nonradiative shock waves

A dynamic theoretical model of grain evolution through steady-state nonradiative shock waves in the Cygnus Loop and Puppis A supernova remnants was constructed. Data from the Rosat position sensitive proportional counter (PSPC) and the Infrared Astronomical Satellite (IRAS) were used. A theoretical model of the grain evolution was developed by using the steady-state nonradiative shocks. Predictions were made concerning the X-ray spectrum emanating from a post-shock plasma were made. The fitting of the model predictions to the spectral shape of the Cygnus Loop X-ray emissions is discussed.

Vancura, O.↗

NASA NTRS2008

Instrument Performance of GISMO, a 2 Millimeter TES Bolometer Camera used at the IRAM 30 m Telescope

In November of 2007 we demonstrated a monolithic Backshort-Under-Grid (BUG) 8x16 array in the field using our 2 mm wavelength imager GISMO (Goddard IRAM Superconducting 2 Millimeter Observer) at the IRAM 30 m telescope in Spain for astronomical observations. The 2 mm spectral range provides a unique terrestrial window enabling ground-based observations of the earliest active dusty galaxies in the universe and thereby allowing a better constraint on the star formation rate in these objects. The optical design incorporates a 100 mm diameter silicon lens cooled to 4 K, which provides the required fast beam yielding 0.9 lambda/D pixels. With this spatial sampling, GISMO will be very efficient at detecting sources serendipitously in large sky surveys, while the capability for diffraction limited imaging is preserved. The camera provides significantly greater detection sensitivity and mapping speed at this wavelength than has previously been possible. The instrument will fill in the spectral energy distribution of high redshift galaxies at the Rayleigh-Jeans part of the dust emission spectrum, even at the highest redshifts. Here1 will we present early results from our observing run with the first fielded BUG bolometer array. We have developed key technologies to enable highly versatile, kilopixel, infrared through millimeter wavelength bolometer arrays. The Backshort-Under-Grid (BUG) array consists of three components: 1) a transition-edge-sensor (TES) based bolometer array with background-limited sensitivity and high filling factor, 2) a quarter-wave reflective backshort grid providing high optical efficiency, and 3) a superconducting bump-bonded large format Superconducting Quantum Interference Device (SQUID) multiplexer readout. The array is described in more detail elsewhere (Allen et al., this conference). In November of 2007 we demonstrated a monolithic 8x 16 array with 2 mm-pitch detectors in the field using our 2 mm wavelength imager GISMO (Goddard IRAM Superconducting 2 Millimeter Observer) at the IRAM 30 m telescope in Spain for astronomical observations. The 2 mm spectral range provides a unique terrestrial window enabling ground-based observations of the earliest active dusty galaxies in the universe and thereby allowing a better constraint on the star formation rate in these objects. The optical design incorporates a 100 mm diameter silicon lens cooled to 4 K, which provides the required fast beam yielding 0.9 lambda1D pixels. With this spatial sampling, GISMO will be very efficient at detecting sources serendipitously in large sky surveys, while the capability for diffraction limited imaging is preserved. The camera provides significantly greater detection sensitivity and mapping speed at this wavelength than has previously been possible. The instrument will fill in the spectral energy distribution of high redshift galaxies at the Rayleigh-Jeans part of the dust emission spectrum, even at the highest redshifts. Here I will we present early results from our observing run with the first fielded BUG bolometer array.

Staguhn, Johannes↗

DOE OSTI2023

Design and Fabrication of Quantum Information Processing Devices (Final Report)

The goal of this work is to develop a wideband Josephson Parametric Amplifier (JPA) by the combination of a coplanar impedance transformer and a lumped Josephson Parametric Amplifier. Josephson Parametric Amplifiers take advantage of the nonlinear inductance of Josephson junctions and the nearly lossless superconductor circuits to achieve wave mixing and amplification with only quantum-limited added noise, which makes it a key component in quantum measurements, such as single-shot qubit measurement. However, the current JPAs generally have a relatively high quality factor and small bandwidth (around 50MHz to 100MHz), which limits their ability in measuring signals from a broad spectrum. Therefore, the work planned to use a coplanar impedance transformer to enhance the coupling between JPA and the signals, resulting in a small quality factor and large bandwidth. By decreasing the quality factor of JPA to around 3, one can achieve around 20dB gain within a bandwidth of several hundred MHz. Moreover, the wideband feature allows this device to explore the frequency dependence of the coupling between the JPA and the signals. Because the impedance transformer is based on a coplanar transmission line and requires no modifications of the lumped JPA, it is relatively straightforward to embed it in the current fabrication, package, and testing process for lumped JPA. The impedance transformer can be fabricated by liftoff or etching process with the lumped JPA together, which adds no fabrication complexity. The only difference is the size, which is around 3~5 times larger than lumped JPA. This may make the number of available chips on a single wafer lower. As for the public benefits, the development of this wideband JPA will make it possible to use just a single JPA device for multi-frequency signals, for example, the readout signals of a superconducting qubit chip with multiplexed readout bus. This would greatly decrease the demand for JPAs in quantum measurements.

42 ENGINEERING↗

NASA NTRS1973

What we think we know and do not know about solar flares

Solar-terrestrial relations begin in the convective zone of the sun. A combination of nonuniform rotation and cyclonic convection generates magnetic fields in migratory waves, which can account for the observed 22-year solar magnetic cycle. The magnetic fields are the active agent in creating the active magnetic regions, with sunspots, prominences, and flares. The present status of knowledge regarding the solar flare phenomenon is reviewed, giving attention to the extraordinary complexity of the solar flare and the broad spectrum of theoretical ideas that have been generated to meet the challenge.

Parker, E. N.↗

NASA NTRS1984

ISEE-3 wave measurements in the distant geomagnetic tail and boundary layer

The ISEE-3 excursion into the distant tail region reveals a complex structure with several wave, particle and field characteristics that differ significantly from those measured closer to earth. The most striking results are found within the distant boundary layer where intense electrostatic turbulence levels are detected in association with bidirectional electron distributions. The wave amplitudes appear to increase with increasing downstream distance and the polarizations are those expected for ion acoustic oscillations. Near the boundary of the distant plasmas sheet the turbulence spectra are essentially identical to those measured much closer to earth on IMP-8. It is also found that in the distant tail the continuum radiation spectrum has a low frequency cutoff that is much higher than the minimum value for the local plasma frequency.

Scarf, F. L.↗

NASA NTRS1993

Lidar and radar derived cirrus microphysical properties for the 26 November 1991 case study

The Wave Propagation Laboratory's CO2 lidar (lambda = 10.6 microns) and Ka-band radar (lambda = 8.66 mm) operate at widely separated wavelengths; the differences in how the transmitted waves interact with cloud targets can be exploited to provide information that neither sensor could provide alone. This can be as simple as overlapping the data sets to provide additional coverage on cloud geometry (see Uttal and Intrieri, 1993) or combining the measurements in a theoretical framework to provide cirrus cloud parameters of the size spectrum, i.e., characteristic particle size and number concentration. In this paper, the latter option is described and an example case study presented to illustrate the types of information available for cloud and radiation transfer models.

Intrieri, Janet M.↗

NASA NTRS1994

Deformation of the total ozone content field in the tropical zone

Presented are the ozone investigation results obtained in the tropical zone. Measurements of the total ozone content (TOC) were carried out by the ozonometer M-124. The ozonometer was automated to investigate the ozone intradiurnal variations and to increase precision of the TOC measurements. Obtained results allowed us to follow the effect of tropical cyclones (TC) on the TOC field. Several days before the TC formation the TOC increase is observed in daily mean course compared with the background one. Three types of trend can be singled out in the TOC intradiurnal course: zero, parabolic, quasi-linear. Maximum velocities of a trend are observed some days before the TC formation. Analogous harmonic constituents are mainly presented as spectrum of daily means of ozone, mean and absolute velocities of trend and dispersion as well as spectra of meteorological, hydrometeorological and actinometric values. Revealed is a number of day-to-day ozone variations concerned with large-scale circulations; moisture content in the atmosphere. Obtained are the data about short-period ozone waves (period less than a day). Thin-film silver sensors were used to measure the vertical ozone distribution (VOD). Atmospheric aerosol and VOD measurements were carried out simultaneously, they gave data of the VOD layered structure, where the VOD local minima coincided with the position of aerosol layers' maxima.

Vasilyev, Victor I.↗

NASA NTRS2002

Thermal Orbital Environmental Parameter Study on the Propulsive Small Expendable Deployer System (ProSEDS) Using Earth Radiation Budget Experiment (ERBE) Data

The natural thermal environmental parameters used on the Space Station Program (SSP 30425) were generated by the Space Environmental Effects Branch at NASA's Marshall Space Flight Center (MSFC) utilizing extensive data from the Earth Radiation Budget Experiment (ERBE), a series of satellites which measured low earth orbit (LEO) albedo and outgoing long-wave radiation. Later, this temporal data was presented as a function of averaging times and orbital inclination for use by thermal engineers in NASA Technical Memorandum TM 4527. The data was not presented in a fashion readily usable by thermal engineering modeling tools and required knowledge of the thermal time constants and infrared versus solar spectrum sensitivity of the hardware being analyzed to be used properly. Another TM was recently issued as a guideline for utilizing these environments (NASA/TM-2001-211221) with more insight into the utilization by thermal analysts. This paper gives a top-level overview of the environmental parameters presented in the TM and a study of the effects of implementing these environments on an ongoing MSFC project, the Propulsive Small Expendable Deployer System (ProSEDS), compared to conventional orbital parameters that had been historically used.

Sharp, John R.↗

DOE OSTI2022

Implementing the three-particle quantization condition for π + π + K + and related systems

Recently, the formalism needed to relate the finite-volume spectrum of systems of nondegenerate spinless particles has been derived. In this work we discuss a range of issues that arise when implementing this formalism in practice, provide further theoretical results that can be used to check the implementation, and make available codes for implementing the three-particle quantization condition. Specifically, we discuss the need to modify the upper limit of the cutoff function due to the fact that the left-hand cut in the scattering amplitudes for two nondegenerate particles moves closer to threshold; we describe the decomposition of the three-particle amplitude K df,3 into the matrix basis used in the quantization condition, including both s and p waves, with the latter arising in the amplitude for two nondegenerate particles; we derive the threshold expansion for the lightest three-particle state in the rest frame up to O(1/L 5 ); and we calculate the leading-order predictions in chiral perturbation theory for K df,3 in the π + π + K + and π + K + K + systems. We focus mainly on systems with two identical particles plus a third that is different (“2+1” systems). We describe the formalism in full detail, and present numerical explorations in toy models, in particular checking that the results agree with the threshold expansion, and making a prediction for the spectrum of π + π + K + levels using the two- and three-particle interactions predicted by chiral perturbation theory.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2022

Room-temperature polariton quantum fluids in halide perovskites

Abstract Quantum fluids exhibit quantum mechanical effects at the macroscopic level, which contrast strongly with classical fluids. Gain-dissipative solid-state exciton-polaritons systems are promising emulation platforms for complex quantum fluid studies at elevated temperatures. Recently, halide perovskite polariton systems have emerged as materials with distinctive advantages over other room-temperature systems for future studies of topological physics, non-Abelian gauge fields, and spin-orbit interactions. However, the demonstration of nonlinear quantum hydrodynamics, such as superfluidity and Čerenkov flow, which is a consequence of the renormalized elementary excitation spectrum, remains elusive in halide perovskites. Here, using homogenous halide perovskites single crystals, we report, in both one- and two-dimensional cases, the complete set of quantum fluid phase transitions from normal classical fluids to scatterless polariton superfluids and supersonic fluids—all at room temperature, clear consequences of the Landau criterion. Specifically, the supersonic Čerenkov wave pattern was observed at room temperature. The experimental results are also in quantitative agreement with theoretical predictions from the dissipative Gross-Pitaevskii equation. Our results set the stage for exploring the rich non-equilibrium quantum fluid many-body physics at room temperature and also pave the way for important polaritonic device applications.

42 ENGINEERING↗

DOE OSTI2022

Minimum stabilizing energy release for mixing processes

Diffusive operations, which mix the populations of different elements of phase space, can irreversibly transform a given initial state into any of a spectrum of different states from which no further energy can be extracted through diffusive operations. We call these ground states. Here, the lower bound of accessible ground-state energies represents the maximal possible release of energy. This lower bound, sometimes called the diffusively accessible free energy, is of interest in theories of instabilities and wave-particle interactions. On the other hand, the upper bound of accessible ground-state energies has escaped identification as a problem of interest. Yet, as demonstrated here, in the case of a continuous system, it is precisely this upper bound that corresponds to the paradigmatic “quasilinear plateau” ground state of the bump-on-tail distribution. Although for general discrete systems the complexity of calculating the upper bound grows rapidly with the number of states, using techniques adapted from treatments of the lower bound, the upper bound can in fact be computed directly for the three-state discrete system.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

NASA NTRS1977

Soft X-ray sources and supernova remnants in Cygnus - Rocket and Apollo-Soyuz results

Soft X-ray observations of the Cygnus region obtained from proportional counters aboard a rocket and also on the Apollo-Soyuz mission are reported. It is found that Cyg X-6, a source whose flux in confined to the 0.5-2.0-keV band, is a long narrow filament oriented nearly perpendicular to the galactic plane. This feature has a linear dimension greater than or of the order of 150 parsecs, and its spectrum is adequately described by an exponential. Another intense soft source whose flux is also confined to the 0.5-2.0-keV band has been discovered near Gamma Cygni. This source, designed Cyg X-7, has a spectrum characterized by a temperature of 1.5 to 5 million K and a hydrogen column density of at least 10 to the 21st power per sq cm. The possible association of Cyg X-7 with the supernova remnant DR 4 is discussed. An interpretation of this object in terms of the standard adiabatic spherical-shock-wave model yields plausible values for the free paramenters. HB 21, another old supernova remnant, has not been detected as a soft X-ray source.

Davidsen, A. F.↗

DOE OSTI2021

Flux Ropes, Turbulence, and Collisionless Perpendicular Shock Waves: High Plasma Beta Case

With the onset of solar maximum and the expected increased prevalence of interplanetary shock waves, Parker Solar Probe is likely to observe numerous shocks in the next few years. An outstanding question that has received surprisingly little attention has been how turbulence interacts with collisionless shock waves. Turbulence in the supersonic solar wind is described frequently as a superposition of a majority 2D and a minority slab component. Here we formulate a collisional perpendicular shock-turbulence transmission problem in a way that enables investigation of the interaction and transmission of quasi-perpendicular fluctuations such as magnetic flux ropes/islands and vortices as well as entropy and acoustic modes in the large plasma beta regime. We focus on the transmission of an upstream spectrum of these modes, finding that the downstream spectral amplitude is typically increased significantly (a factor of 10 or more), and that the upstream spectral index of the inertial range, and indeed the general spectral shape, is unchanged for the downstream magnetic variance, kinetic energy, and density variance. A comparison of the theoretically predicted downstream magnetic variance, kinetic energy, and density variance spectra with those observed at 1, 5, and 84 au by Wind, Ulysses, and Voyager 2 shows excellent agreement. The overall theoretically predicted characteristics of the transmission of turbulence across shocks observed in the solar wind appear to be largely consistent with recent observational studies by Pitňa et al. and Borovsky.

79 ASTRONOMY AND ASTROPHYSICS↗

NASA NTRS1983

An investigation of turbulent scatter from the mesosphere as observed by coherent-scatter radar

Turbulent scatter from he mesosphere is observed using the Urbana coherent-scatter radar. The variation in signal-to-noise ratio as a function of time-of-day is examined. The origin of scattering regions is investigated by comparing the variations in scattered power and Doppler velocity. Nighttime echoes are shown for periods of enhanced electron concentration. The spectrum of the returned signal is studied with a resolution of ten seconds. Spectral information is used to increase altitude resolution and observe the motion of scatterers. The expected variation in signal-to-noise ratio with solar flux is observed. It is found that variations in the scattered power generally do not correspond to the gravity waves which are simultaneously observed. Turbulent layers are observed at altitudes with high shear in the horizontal velocity and at altitudes with low shear. The ten-second resolution is necessary to distinguish meteor echoes from echoes produced by the advection of a scattering layer through the radar beam.

Gibbs, K. P.↗