Showing papers by "Raytheon published in 2018"

Age Determinations of the Hyades, Praesepe, and Pleiades via MESA Models with Rotation

Abstract: The Hyades, Praesepe, and Pleiades are well studied stellar clusters that anchor important secondary stellar age indicators. Recent studies have shown that main sequence turn off-based ages for these clusters may depend on the degree of rotation in the underlying stellar models. Rotation induces structural instabilities that can enhance the chemical mixing of a star, extending its fuel supply. In addition, rotation introduces a modulation of the star's observed magnitude and color due to the effects of gravity darkening. We aim to investigate the extent to which stellar rotation affects the age determination of star clusters. We utilize the MESA stellar evolution code to create models that cover a range of rotation rates corresponding to $\Omega/\Omega_c=0.0$ to $0.6$ in $0.1$ dex steps, allowing the assessment of variations in this dimension. The statistical analysis package, MATCH, is employed to derive ages and metallicities by fitting our MESA models to Tycho $B_T$, $V_T$ and 2MASS $J$, $K_s$ color-magnitude diagrams. We find that the derived ages are relatively insensitive to the effects of rotation. For the Hyades, Praesepe, and Pleiades, we derive ages based on synthetic populations that model a distribution of rotation rates or a fixed rate. Across each case, derived ages tend to agree roughly within errors, near $680$, $590$, and $110-160$ Myr for the Hyades, Praesepe, and Pleiades, respectively. These ages are in agreement with Li depletion boundary-based ages and previous analyses that used non-rotating isochrones. Our methods do not provide a strong constraint on the metallicities of these clusters.

OpenWorm: overview and recent advances in integrative biological simulation of Caenorhabditis elegans.

Abstract: The adoption of powerful software tools and computational methods from the software industry by the scientific research community has resulted in a renewed interest in integrative, large-scale biol

Age Determinations of the Hyades, Praesepe, and Pleiades via MESA Models with Rotation

Abstract: The Hyades, Praesepe, and Pleiades are well studied stellar clusters that anchor important secondary stellar age indicators. Recent studies have shown that main sequence turn off-based ages for these clusters may depend on the degree of rotation in the underlying stellar models. Rotation induces structural instabilities that can enhance the chemical mixing of a star, extending its fuel supply. In addition, rotation introduces a modulation of the star's observed magnitude and color due to the effects of gravity darkening. We aim to investigate the extent to which stellar rotation affects the age determination of star clusters. We utilize the MESA stellar evolution code to create models that cover a range of rotation rates corresponding to $\Omega/\Omega_c=0.0$ to $0.6$ in $0.1$ dex steps, allowing the assessment of variations in this dimension. The statistical analysis package, MATCH, is employed to derive ages and metallicities by fitting our MESA models to Tycho $B_T$, $V_T$ and 2MASS $J$, $K_s$ color-magnitude diagrams. We find that the derived ages are relatively insensitive to the effects of rotation. For the Hyades, Praesepe, and Pleiades, we derive ages based on synthetic populations that model a distribution of rotation rates or a fixed rate. Across each case, derived ages tend to agree roughly within errors, near $680$, $590$, and $110-160$ Myr for the Hyades, Praesepe, and Pleiades, respectively. These ages are in agreement with Li depletion boundary-based ages and previous analyses that used non-rotating isochrones. Our methods do not provide a strong constraint on the metallicities of these clusters.

A Complete Census of Luminous Stellar Variability on Day to Decade Timescales

Abstract: Stellar photometric variability offers a novel probe of the interior structure and evolutionary state of stars. Here we present a census of stellar variability on day to decade timescales across the color-magnitude diagram for 73,000 stars brighter than $M_I$=-5 in the Whirlpool Galaxy (M51). Our Cycle 24 HST program acquired V and I-band images over 34 epochs spanning one year with pseudo-random cadences enabling sensitivity to periods from days to months. We supplement these data with archival V and I-band HST data obtained in 1995 and 2005 providing sensitivity to variability on decade timescales. At least 50% of stars brighter than $M_I$=-7 show strong evidence for variability within our Cycle 24 data; among stars with V-I>2 the variability fraction rises to ~100%. Large amplitude variability (>0.3 mag) on decade timescales is restricted to red supergiants and very luminous blue stars. Both populations display fairly smooth variability on month-year timescales. The Cepheid instability strip is clearly visible in our data, although the variability fraction within this region never exceeds ~10%. The location of variable stars across the color magnitude diagram broadly agrees with theoretical sources of variability, including the instability strip, red supergiant pulsational instabilities, long-period fundamental mode pulsations, and radiation-dominated envelopes in massive stars. Our data can be used to place stringent constraints on the precise onset of these various instabilities and their lifetimes and growth rates.

Atmospheric Humidity Sounding Using Differential Absorption Radar Near 183 GHz

Abstract: A tunable G-band frequency-modulated continuous-wave radar system has been developed and used to perform differential absorption atmospheric humidity measurements for the first time. The radar’s transmitter uses high- power-handling GaAs Schottky diodes to generate between 15–23 dBm over a 10-GHz bandwidth near 183 GHz. By virtue of a high-isolation circular polarization duplexer, the monostatic radar’s receiver maintains a noise figure of about 7 dB even while the transmitter is on. With an antenna gain of 40 dB, high-SNR detection of light rain is achieved out to several hundred meters distance. Owing to the strong spectral dependence of the atmospheric absorption over the upper flank of the 183-GHz water absorption line, range-resolved measurements of absolute humidity can be obtained by ratioing the rain echoes over both range and frequency. Absorption measurements obtained are consistent with models of atmospheric millimeter-wave attenuation, and they demonstrate a new method for improving the accuracy of humidity measurements inside of clouds.

Formation time-scales for high-mass X-ray binaries in M33

Abstract: We have identified 55 candidate high-mass X-ray binaries (HMXBs) in M33 using available archival {\it HST} and {\it Chandra} imaging to find blue stars associated with X-ray positions. We use the {\it HST} photometric data to model the color-magnitude diagrams in the vicinity of each candidate HMXB to measure a resolved recent star formation history (SFH), and thus a formation timescale, or age for the source. Taken together, the SFHs for all candidate HMXBs in M33 yield an age distribution that suggests preferred formation timescales for HMXBs in M33 of $<$ 5 Myr and $\sim$ 40 Myr after the initial star formation episode. The population at 40 Myr is seen in other Local Group galaxies, and can be attributed to a peak in formation efficiency of HMXBs with neutron stars as compact objects and B star secondary companions. This timescale is preferred as neutron stars should form in abundance from $\sim$ 8 M$_{\odot}$ core-collapse progenitors on these timescales, and B stars are shown observationally to be most actively losing mass around this time. The young population at $<$ 5 Myr has not be observed in other Local Group HMXB population studies, but may be attributed to a population of very massive progenitors forming black holes very early on. We discuss these results in the context of massive binary evolution, and the implications for compact object binaries and gravitational wave sources.

New Theory and Numerical Results for Gromov's Method for Stochastic Particle Flow Filters

Abstract: We derive a new exact stochastic particle flow for Bayes' rule using a theorem of Gromov. We also show numerical experiments for high dimensional problems up to $\mathbf{d}=100$ . The accuracy of our new filter is many orders of magnitude better than standard particle filters, and our filter beats the EKF by orders of magnitude for difficult nonlinear problems. The new theoretical result is valid for arbitrary smooth nowhere vanishing densities, whereas our previous theory was derived for the special case of Gaussian densities with linear measurements. It is crucial to mitigate stiffness of the flow in order to achieve good numerical results.

Progenitor Mass Distribution for Core-collapse Supernova Remnants in M31 and M33

Abstract: Using the star formation histories (SFHs) near 94 supernova remnants (SNRs), we infer the progenitor mass distribution for core-collapse supernovae. We use Bayesian inference and model each SFH with multiple bursts of star formation (SF), one of which is assumed to be associated with the SNR. Assuming single-star evolution, the minimum mass of CCSNe is $7.33^{+0.02}_{-0.16}$ $\text{M}_\odot$, the slope of the progenitor mass distribution is $\alpha = -2.96^{+0.45}_{-0.25}$, and the maximum mass is greater than $\text{M}_\textrm{max} > 59$ $\text{M}_\odot$ with a 68% confidence. While these results are consistent with previous inferences, they also provide tighter constraints. The progenitor distribution is somewhat steeper than a Salpeter initial mass function ($\alpha$ = -2.35). This suggests that either SNR catalogs are biased against the youngest SF regions, or the most massive stars do not explode as easily as lower mass stars. If SNR catalogs are biased, it will most likely affect the slope but not the minimum mass. The uncertainties are dominated by three primary sources of uncertainty, the SFH resolution, the number of SF bursts, and the uncertainty on SF rate in each age bin. We address the first two of these uncertainties, with an emphasis on multiple bursts. The third will be addressed in future work.

Systems and methods for detecting damage

Abstract: A system and method of detecting damage to a component may include a first sensor and a processor. The method may include the steps of receiving, by the processor, a first data for the component from a first sensor, aligning, by the processor, the first data with a reference model, determining, by the processor, a feature dissimilarity between the first data and the reference model, classifying, by the processor, the feature dissimilarity, and determining, by the processor, a probability that the feature dissimilarity indicates damage to the component.

Systems and methods for demodulation of free space optical signals without wavefront correction

Abstract: Optical signal receivers and methods are provided that include an optical resonator that allows an optical signal to enter and optical signal energy to accumulate at regions inside the optical resonator. A portion of optical signal energy is emitted from among various regions of the optical resonator, such that a combination of the emitted optical signal energy is disturbed when a phase transition occurs in the received optical signal. A detector aligned with the output detects the combined emitted optical signal energy and is configured to detect the disturbance and determine a characteristic of the phase transition in the received optical signal based upon the disturbance.

Floating non-contact seal vertical lip

Abstract: A seal assembly includes an annular base, a spring, a shoe, a first channel, a seal cover, and a seal. The spring includes a beam and is connected to the annular base. The shoe is disposed radially inward of the annular base and connected to the spring. The shoe includes an upstream portion, a downstream portion, and a lip connected to and extending radially outward from the upstream portion of the shoe. The spring extends from the annular base to the shoe. The first channel is positioned between the shoe and the beam of the spring. The seal is disposed between the seal cover and the shoe such that a downstream face of the seal is in contact with an upstream face of the shoe.

Monitoring Algal Blooms in drinking water reservoirs using the Landsat 8 Operational Land Imager.

Abstract: In this study, we demonstrated that the Landsat-8 Operational Land Imager (OLI) sensor is a powerful tool that can provide periodic and system-wide information on the condition of drinking water reservoirs. The OLI is a multispectral radiometer (30 m spatial resolution) that allows ecosystem observations at spatial and temporal scales that allow the environmental community and water managers another means to monitor changes in water quality not feasible with field-based monitoring. Using the provisional Land Surface Reflectance (LSR) product and field-collected chlorophyll-a (chl-a) concentrations from drinking water monitoring programs in North Carolina and Rhode Island, we compared five established approaches for estimating chl-a concentrations using spectral data. We found that using the 3 band reflectance approach with a combination of OLI spectral bands 1, 3, and 5, produced the most promising results for accurately estimating chl-a concentrations in lakes (R2 value of 0.66; RMSE value of 8.9 μg l-1). Using this model, we forecast the spatial and temporal variability of chl-a for Jordan Lake, a recreational and drinking water source in piedmont North Carolina and several small ponds that supply drinking water in southeastern Rhode Island.

Investigating the Electron–Phonon Coupling of Molecular Beam Epitaxy-Grown Hg 1−x Cd x Se Semiconductor Alloys

Abstract: Using spectroscopic ellipsometry, the temperature-dependence of the dielectric functions of a series of Hg1−xCdxSe thin films deposited on both ZnTe/Si(112) and GaSb(112) substrates were investigated. Initially, for each sample, room-temperature ellipsometric spectra were obtained from 35 meV to 6 eV using two different ellipsometers. Subsequently, ellipsometry spectra were obtained from 10 K to 300 K by incorporating a cryostat to the ellipsometer. Using a standard inversion technique, the spectroscopic ellipsometric data were modeled in order to obtain the temperature-dependent dielectric functions of each of the Hg1−xCdxSe thin films. The results indicate that the E1 critical point blue-shifts as a function of Cd-alloy concentration. The temperature-dependence of E1 was fitted to a Bose–Einstein occupation distribution function, which consequently allowed us to determine the electron–phonon coupling of Hg1−xCdxSe alloys. From the fitting results, we obtain a value of 17 ± 2 meV for the strength of the electron–phonon coupling for Hg1−xCdxSe alloy system, which compares nominally with the binary systems, such as CdSe and CdTe, which have values around 38 meV and 16 meV, respectively. This implies that the addition of Hg into the CdSe binary system does not significantly alter its electron–phonon coupling strength. Raman spectroscopy measurements performed on all the samples show the HgSe-like transverse optic (TO) and longitudinal optic (LO) phonons (∼ 130 cm−1 and ∼ 160 cm−1, respectively) for all the samples. While there is a slight red-shift of the HgSe-like TO peak as a function of the Cd-concentration, HgSe-like LO peak does not significantly change with the alloy concentration.

Gallium nitride amplifiers beyond W-band

Abstract: We have developed gallium nitride (GaN) monolithic microwave integrated circuit (MMIC) amplifiers that span different frequency ranges from Q-band (33–50 GHz) into G-band (140–220 GHz). We have designed, fabricated and tested a broadband amplifier with more than 11 dB of gain from 38 GHz to at least 110 GHz, and a broadband amplifier with gain across all of F-band (90–140 GHz) with peak gain of 18.9 dB and noise figure of 7.4 dB at 120 GHz. In G-band we have developed an amplifier with 8.7 dB small-signal gain at 149 GHz, and when two such amplifiers were placed in series, large signal power measurements gave 18.2 dBm of output RF power and 10 dB gain at 147 GHz. These results demonstrate 0.15 μm gate length GaN HEMTs are applicable for amplifiers through F-band and into G-band.

The Progenitor Age and Mass of the Black-Hole-Formation Candidate N6946-BH1

Abstract: The failed supernova N6946-BH1 likely formed a black hole (BH); we age-date the surrounding population and infer an age and initial mass for the progenitor of this BH formation candidate. First, we use archival Hubble Space Telescope imaging to extract broadband photometry of the resolved stellar populations surrounding this event. Using this photometry, we fit stellar evolution models to the color-magnitude diagrams to measure the recent star formation history (SFH). Modeling the photometry requires an accurate distance; therefore, we measure the tip of the red giant branch (TRGB) and infer a distance modulus of $29.47 \pm 0.079$ to NGC~6946, or a metric distance of $7.83 \pm 0.29$ Mpc. To estimate the stellar population's age, we convert the SFH and uncertainties into a probabilistic distribution for the progenitor's age. The region in the immediate vicinity of N6946-BH1 exhibits the youngest and most vigorous star formation for several hundred pc. This suggests that the progenitor is not a runaway star. From these measurements, we infer an age for the BH progenitor of $10.6^{+14.5}_{-5.9}$ Myr. Assuming that the progenitor evolved effectively as a single star, this corresponds to an initial mass of $17.9^{+29.9}_{-7.6}$ $M_{\odot}$. Previous spectral energy distribution (SED) modeling of the progenitor suggests a mass of $\sim$27 $M_{\odot}$. Formally, the SED-derived mass falls within our narrowest 68\% confidence interval; however, $91\%$ of the probability distribtuion function we measure lies below that mass, putting some tension between the age and the direct-imaging results.

Autonomous system and method for redundancy management of multiple power supplies

Abstract: A system includes an output terminal to couple to an electrical load and a plurality of power supplies coupled in parallel. Each of the power supplies includes a controller configured to monitor a power output of a downstream power supply and a power output of an upstream power supply, maintain a standby state of the power supply in response to the downstream power supply providing power below a first threshold value, transition the power supply to an voltage regulation state in response to the downstream power supply providing power above the first threshold value, and provide a maximum power in response to the upstream power supply providing power above a second threshold value. The standby state represents a state in which a power output of the power supply is 0%, and the voltage regulation state representing a state in which the power output of the power supply is above 0%.

The Progenitor Age and Mass of the Black Hole Formation Candidate N6946-BH1

Abstract: The failed supernova N6946-BH1 likely formed a black hole (BH); we age-date the surrounding population and infer an age and initial mass for the progenitor of this BH formation candidate. First, we use archival Hubble Space Telescope imaging to extract broadband photometry of the resolved stellar populations surrounding this event. Using this photometry, we fit stellar evolution models to the color-magnitude diagrams to measure the recent star formation history (SFH). Modeling the photometry requires an accurate distance; therefore, we measure the tip of the red giant branch (TRGB) and infer a distance modulus of $29.47 \pm 0.079$ to NGC~6946, or a metric distance of $7.83 \pm 0.29$ Mpc. To estimate the stellar population's age, we convert the SFH and uncertainties into a probabilistic distribution for the progenitor's age. The region in the immediate vicinity of N6946-BH1 exhibits the youngest and most vigorous star formation for several hundred pc. This suggests that the progenitor is not a runaway star. From these measurements, we infer an age for the BH progenitor of $10.6^{+14.5}_{-5.9}$ Myr. Assuming that the progenitor evolved effectively as a single star, this corresponds to an initial mass of $17.9^{+29.9}_{-7.6}$ $M_{\odot}$. Previous spectral energy distribution (SED) modeling of the progenitor suggests a mass of $\sim$27 $M_{\odot}$. Formally, the SED-derived mass falls within our narrowest 68\% confidence interval; however, $91\%$ of the probability distribtuion function we measure lies below that mass, putting some tension between the age and the direct-imaging results.

Combustor liner panel end rail angled cooling interface passage for a gas turbine engine combustor

Abstract: A combustor for a gas turbine engine includes a support shell with an angled shell interface; a first liner panel mounted to the support shell via a multiple of studs, the first liner panel including a first rail that extends from a cold side of the first liner panel adjacent to the angled shell interface; and a second liner panel mounted to the support shell via a multiple of studs, the second liner panel including a second rail that extends from a cold side of the second liner panel adjacent to said first rail, the second rail adjacent to the angled shell interface.

A Complete Census of Luminous Stellar Variability on Day to Decade Timescales

Abstract: Stellar photometric variability offers a novel probe of the interior structure and evolutionary state of stars. Here we present a census of stellar variability on day to decade timescales across the color-magnitude diagram for 73,000 stars brighter than $M_I$=-5 in the Whirlpool Galaxy (M51). Our Cycle 24 HST program acquired V and I-band images over 34 epochs spanning one year with pseudo-random cadences enabling sensitivity to periods from days to months. We supplement these data with archival V and I-band HST data obtained in 1995 and 2005 providing sensitivity to variability on decade timescales. At least 50% of stars brighter than $M_I$=-7 show strong evidence for variability within our Cycle 24 data; among stars with V-I>2 the variability fraction rises to ~100%. Large amplitude variability (>0.3 mag) on decade timescales is restricted to red supergiants and very luminous blue stars. Both populations display fairly smooth variability on month-year timescales. The Cepheid instability strip is clearly visible in our data, although the variability fraction within this region never exceeds ~10%. The location of variable stars across the color magnitude diagram broadly agrees with theoretical sources of variability, including the instability strip, red supergiant pulsational instabilities, long-period fundamental mode pulsations, and radiation-dominated envelopes in massive stars. Our data can be used to place stringent constraints on the precise onset of these various instabilities and their lifetimes and growth rates.

Challenges and opportunities in Gen3 embedded cooling with high-quality microgap flow

Abstract: Gen3, Embedded Cooling, promises to revolutionize thermal management of advanced microelectronic systems by eliminating the sequential conductive and interfacial thermal resistances which dominate the present “remote cooling” paradigm. Single-phase interchip microfluidic flow with high thermal conductivity chips and substrates has been used successfully to cool single transistors dissipating more than 40kW/cm2, but efficient heat removal from transistor arrays, larger chips, and chip stacks operating at these prodigious heat fluxes would require the use of high vapor fraction (quality), two-phase cooling in intra- and inter-chip microgap channels. The motivation, as well as the challenges and opportunities associated with evaporative embedded cooling in realistic form factors, is the focus of this paper. The paper will begin with a brief review of the history of thermal packaging, reflecting the 70-year “inward migration” of cooling technology from the computer-room, to the rack, and then to the single chip and multichip module with — and liquid-cooled coldplates. Discussion of the limitations of this approach and recent results from single-phase embedded cooling will follow. This will set the stage for discussion of the development challenges associated with application of this Gen3 thermal management paradigm to commercial semiconductor hardware, including dealing with the effects of channel length, orientation, and manifold-driven centrifugal acceleration on the governing behavior.

Receivers and method for detecting a non-persistent communication superimposed on an overt communication channel

Abstract: Aspects are generally directed to optical receivers and methods for detecting a non-persistent communication superimposed on an overt communication channel. In one example, an optical receiver includes an optical resonator to receive an optical signal having one or more symbols encoded thereon at a modulated symbol repetition rate, the modulated symbol repetition rate being modulated relative to a nominal symbol repetition rate. The optical resonator is configured to emit an intensity-modulated output optical signal that has a variation in an intensity thereof corresponding to a symbol transition in the optical signal. The optical receiver further includes signal processing circuitry including a clock configured to generate a reference signal, a photodetector configured to generate a trigger signal, and a non-persistent communication decoder configured to determine a temporal misalignment between the symbol transition and the nominal symbol repetition rate based on the reference signal and the trigger signal.

Progenitor Mass Distribution for Core-Collapse Supernova Remnants in M31 and M33.

Abstract: Using the star formation histories (SFHs) near 94 supernova remnants (SNRs), we infer the progenitor mass distribution for core-collapse supernovae. We use Bayesian inference and model each SFH with multiple bursts of star formation (SF), one of which is assumed to be associated with the SNR. Assuming single-star evolution, the minimum mass of CCSNe is $7.33^{+0.02}_{-0.16}$ $\text{M}_\odot$, the slope of the progenitor mass distribution is $\alpha = -2.96^{+0.45}_{-0.25}$, and the maximum mass is greater than $\text{M}_\textrm{max} > 59$ $\text{M}_\odot$ with a 68% confidence. While these results are consistent with previous inferences, they also provide tighter constraints. The progenitor distribution is somewhat steeper than a Salpeter initial mass function ($\alpha$ = -2.35). This suggests that either SNR catalogs are biased against the youngest SF regions, or the most massive stars do not explode as easily as lower mass stars. If SNR catalogs are biased, it will most likely affect the slope but not the minimum mass. The uncertainties are dominated by three primary sources of uncertainty, the SFH resolution, the number of SF bursts, and the uncertainty on SF rate in each age bin. We address the first two of these uncertainties, with an emphasis on multiple bursts. The third will be addressed in future work.

Auxiliary journal oil supply system

Abstract: A fluid circulation system may comprise a main pump configured to provide oil to a journal bearing. An auxiliary system including a pump system may be configured to provide oil to the journal bearing. A manifold may be configured to mix the oil from the main pump with oil from the auxiliary system. A journal delivery line may be configured to deliver the oil from the manifold to the journal bearing.

System and method for concurrent communication of different signal types by a radar

Abstract: A method for concurrent transmission of different signal types by a radar system includes: receiving a waveform request for transmitting a first signal type and a second signal type; determining whether the first signal or the second signal is optimized; when the first signal is optimized: transmitting the first and the second signal simultaneously in separate bands; and when the second signal is optimized: determining a time gap between transmission of the second signal, and adjusting pulse repetition interval (PRI) or pulse width of the first signal to fit in the time gap, transmitting the second signal, and transmitting the first signal in the time gap between the transmission of the second signal.

UV Thermal Imaging of RF GaN Devices with GaN Resistor Validation

Abstract: Shrinking features and growing device complexity in advanced microwave devices has increased the challenge of fully understanding device thermal behavior on the sub-micron scale. Predicting the device static and dynamic thermal behavior is essential for ensuring optimal tradeoffs between performance and device reliability. Thermal imaging based on the Thermoreflectance Principle can meet the challenges imposed by these compact, high power density RF devices by providing submicron spatial resolution and temporal resolution in the picosecond range. This technique overcomes the limitations of traditional thermal imaging techniques such as IR and Micro-Raman and some of the specific challenges in measuring GaN devices. In the past, Thermoreflectance Imaging has been shown to accurately estimate the temperature rise of metals using visible wavelength excitation sources. This paper presents a novel method to estimate the temperature directly on GaN surfaces using UV wavelengths. These UV thermoreflectance measurements were verified with measurement of an on-chip GaN mesa resistor. Temperature measurements on top of the field plate and inside the GaN channel were compared for a commercial GaN HEMT both on Si and SiC substrate. The advantages and disadvantages will be presented for the thermoreflectance technique for thermal imaging.

Experimental platform for investigations of high-intensity laser plasma interactions in the magnetic field of a pulsed power generator.

Abstract: An experimental platform for the studying of high-intensity laser plasma interactions in strong magnetic fields has been developed based on the 1 MA Zebra pulsed power generator coupled with the 50-TW Leopard laser. The Zebra generator produces 100-300 T longitudinal and transverse magnetic fields with different types of loads. The Leopard laser creates plasma at an intensity of 1019 W/cm2 in the magnetic field of coil loads. Focusing and targeting systems are integrated in the vacuum chamber of the pulsed power generator and protected from the plasma debris and strong mechanical shock. The first experiments with plasma at laser intensity >2 × 1018 W/cm2 demonstrated collimation of the laser produced plasma in the axial magnetic field strength >100 T.

Systems and methods for demodulation of wave division multiplexed optical signals

Abstract: Optical signal receivers and methods are provided that include an optical resonator that allows optical signal energy of multiple wavelengths to enter and accumulate inside the optical resonator. A portion of optical signal energy of each wavelength is emitted from the optical resonator at an output, and the individual wavelengths may be separated. A detector aligned with the output detects the emitted optical signal energy of at least one of the wavelengths. The detector is configured to detect disturbances to the emitted optical signal energy and determine a modulated characteristic in the received optical signal energy of the wavelength.

Systems and methods for concealing waveform properties

Abstract: Aspects are generally directed to free-space transmitters, free-space receivers, and free-space communication methods. In one example, a free-space communication method includes acts of mapping a data payload to one or more symbols based on a symbol set defined by a digital modulation scheme, varying one or more properties of a signal waveform to phase modulate the signal waveform with the data payload, the one or more symbols each having a symbol duration that defines a timing structure of the modulated signal waveform, and fragmenting the timing structure of the modulated signal waveform to conceal one or more waveform properties of the modulated signal waveform.