NASA’s Solar Dynamics Observatory Captured Trio of Solar Flares April 2-3

NASA Image and Video Library

2017-12-08

The sun emitted a trio of mid-level solar flares on April 2-3, 2017. The first peaked at 4:02 a.m. EDT on April 2, the second peaked at 4:33 p.m. EDT on April 2, and the third peaked at 10:29 a.m. EDT on April 3. NASA’s Solar Dynamics Observatory, which watches the sun constantly, captured images of the three events. Solar flares are powerful bursts of radiation. Harmful radiation from a flare cannot pass through Earth's atmosphere to physically affect humans on the ground, however — when intense enough — they can disturb the atmosphere in the layer where GPS and communications signals travel. Learn more: go.nasa.gov/2oQVFju Caption: NASA's Solar Dynamics Observatory captured this image of a solar flare peaking at 10:29 a.m. EDT on April 3, 2017, as seen in the bright flash near the sun’s upper right edge. The image shows a subset of extreme ultraviolet light that highlights the extremely hot material in flares and which is typically colorized in teal. Credits: NASA/SDO NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Solar array flight dynamic experiment

NASA Technical Reports Server (NTRS)

Schock, R. W.

1986-01-01

The purpose of the Solar Array Flight Dynamic Experiment (SAFDE) is to demonstrate the feasibility of on-orbit measurement and ground processing of large space structures dynamic characteristics. Test definition or verification provides the dynamic characteristic accuracy required for control systems use. An illumination/measurement system was developed to fly on space shuttle flight STS-31D. The system was designed to dynamically evaluate a large solar array called the Solar Array Flight Experiment (SAFE) that had been scheduled for this flight. The SAFDE system consisted of a set of laser diode illuminators, retroreflective targets, an intelligent star tracker receiver and the associated equipment to power, condition, and record the results. In six tests on STS-41D, data was successfully acquired from 18 retroreflector targets and ground processed, post flight, to define the solar array's dynamic characteristic. The flight experiment proved the viability of on-orbit test definition of large space structures dynamic characteristics. Future large space structures controllability should be greatly enhanced by this capability.

Solar array flight dynamic experiment

NASA Technical Reports Server (NTRS)

Schock, Richard W.

1986-01-01

The purpose of the Solar Array Flight Dynamic Experiment (SAFDE) is to demonstrate the feasibility of on-orbit measurement and ground processing of large space structures dynamic characteristics. Test definition or verification provides the dynamic characteristic accuracy required for control systems use. An illumination/measurement system was developed to fly on Space Shuttle flight STS-31D. The system was designed to dynamically evaluate a large solar array called the Solar Array Flight Experiment (SAFE) that had been scheduled for this flight. The SAFDE system consisted of a set of laser diode illuminators, retroreflective targets, an intelligent star tracker receiver and the associated equipment to power, condition, and record the results. In six tests on STS-41D, data was successfully acquired from 18 retroreflector targets and ground processed, post flight, to define the solar array's dynamic characteristic. The flight experiment proved the viability of on-orbit test definition of large space structures dynamic characteristics. Future large space structures controllability should be greatly enhanced by this capability.

Solar array flight dynamic experiment

NASA Technical Reports Server (NTRS)

Schock, Richard W.

1987-01-01

The purpose of the Solar Array Flight Dynamic Experiment (SAFDE) is to demonstrate the feasibility of on-orbit measurement and ground processing of large space structures' dynamic characteristics. Test definition or verification provides the dynamic characteristic accuracy required for control systems use. An illumination/measurement system was developed to fly on space shuttle flight STS-41D. The system was designed to dynamically evaluate a large solar array called the Solar Array Flight Experiment (SAFE) that had been scheduled for this flight. The SAFDE system consisted of a set of laser diode illuminators, retroreflective targets, an intelligent star tracker receiver and the associated equipment to power, condition, and record the results. In six tests on STS-41D, data was successfully acquired from 18 retroreflector targets and ground processed, post flight, to define the solar array's dynamic characteristic. The flight experiment proved the viability of on-orbit test definition of large space structures dynamic characteristics. Future large space structures controllability should be greatly enhanced by this capability.

NREL Evaluates Advanced Solar Inverter Performance for Hawaiian Electric

Science.gov Websites

Companies | Energy Systems Integration Facility | NREL NREL Evaluates Advanced Solar Inverter Performance for Hawaiian Electric Companies NREL Evaluates Advanced Solar Inverter Performance for Hawaiian performance and impacts of today's advanced solar inverters, as well as proprietary feedback to the inverter

Dynamics of Magnetopause Reconnection in Response to Variable Solar Wind Conditions

NASA Astrophysics Data System (ADS)

Berchem, J.; Richard, R. L.; Escoubet, C. P.; Pitout, F.

2017-12-01

Quantifying the dynamics of magnetopause reconnection in response to variable solar wind driving is essential to advancing our predictive understanding of the interaction of the solar wind/IMF with the magnetosphere. To this end we have carried out numerical studies that combine global magnetohydrodynamic (MHD) and Large-Scale Kinetic (LSK) simulations to identify and understand the effects of solar wind/IMF variations. The use of the low dissipation, high resolution UCLA MHD code incorporating a non-linear local resistivity allows the representation of the global configuration of the dayside magnetosphere while the use of LSK ion test particle codes with distributed particle detectors allows us to compare the simulation results with spacecraft observations such as ion dispersion signatures observed by the Cluster spacecraft. We present the results of simulations that focus on the impacts of relatively simple solar wind discontinuities on the magnetopause and examine how the recent history of the interaction of the magnetospheric boundary with solar wind discontinuities can modify the dynamics of magnetopause reconnection in response to the solar wind input.

Advanced Solar Panel Designs

NASA Technical Reports Server (NTRS)

Ralph, E. L.; Linder, E. B.

1995-01-01

Solar panel designs that utilize new high-efficiency solar cells and lightweight rigid panel technologies are described. The resulting designs increase the specific power (W/kg) achievable in the near-term and are well suited to meet the demands of higher performance small satellites (smallsats). Advanced solar panel designs have been developed and demonstrated on two NASA SBIR contracts at Applied Solar. The first used 19% efficient, large area (5.5 cm x 6.5 cm) GaAs/Ge solar cells with a lightweight rigid graphite epoxy isogrid substrate configuration. A 1,445 sq cm coupon was fabricated and tested to demonstrate 60 W/kg with a high potential of achieving 80 W/kg. The second panel design used new 22% efficiency, dual-junction GaInP2/GaAs/Ge solar cells combined with a lightweight aluminum core/graphite fiber mesh facesheet substrate. A 1,445 sq cm coupon was fabricated and tested to demonstrate 105 W/kg with the potential of achieving 115 W/kg.

Technology Projections for Solar Dynamic Power

NASA Technical Reports Server (NTRS)

Mason, Lee S.

1999-01-01

Solar Dynamic power systems can offer many potential benefits to Earth orbiting satellites including high solar-to-electric efficiency, long life without performance degradation, and high power capability. A recent integrated system test of a 2 kilowatt SD power system in a simulated space environment has successfully demonstrated technology readiness for space flight. Conceptual design studies of SD power systems have addressed several potential mission applications: a 10 kilowatt LEO satellite, a low power Space Based Radar, and a 30 kilowatt GEO communications satellite. The studies show that with moderate component development, SD systems can exhibit excellent mass and deployed area characteristics. Using the conceptual design studies as a basis, a SD technology roadmap was generated which identifies the component advances necessary to assure SD systems a competitive advantage for future NASA, DOD, and commercial missions.

Compatibility of molten salts with advanced solar dynamic receiver materials

NASA Technical Reports Server (NTRS)

Jaworske, D. A.; Perry, W. D.

1989-01-01

Metal-coated graphite fibers are being considered as a thermal conductivity enhancement filler material for molten salts in solar dynamic thermal energy storage systems. The successful metal coating chosen for this application must exhibit acceptable wettability and must be compatible with the molten salt environment. Contact angle values between molten lithium fluoride and several metal, metal fluoride, and metal oxide substrates have been determined at 892 C using a modification of the Wilhelmy plate technique. Reproducible contact angles with repeated exposure to the molten LiF indicated compatibility.

Solar Concentrator Advanced Development Program

NASA Technical Reports Server (NTRS)

Knasel, Don; Ehresman, Derik

1989-01-01

The Solar Concentrator Advanced Development Project has successfully designed, fabricated, and tested a full scale prototypical solar dynamic concentrator for space station applications. A Truss Hexagonal Panel reflector was selected as a viable solar concentrator concept to be used for space station applications. This concentrator utilizes a modular design approach and is flexible in attainable flux profiles and assembly techniques. The detailed design of the concentrator, which included structural, thermal and optical analysis, identified the feasibility of the design and specific technologies that were required to fabricate it. The needed surface accuracy of the reflectors surface was found to be very tight, within 5 mrad RMS slope error, and results in very close tolerances for fabrication. To meet the design requirements, a modular structure composed of hexagonal panels was used. The panels, made up of graphite epoxy box beams provided the strength, stiffness and dimensional stability needed. All initial project requirements were met or exceeded by hardware demonstration. Initial testing of structural repeatability of a seven panel portion of the concentrator was followed by assembly and testing of the full nineteen panel structure. The testing, which consisted of theodolite and optical measurements over an assembly-disassembly-reassembly cycle, demonstrated that the concentrator maintained the as-built contour and optical characteristics. The facet development effort within the project, which included developing the vapor deposited reflective facet, produced a viable design with demonstrated optical characteristics that are within the project goals.

Advanced instrumentation for Solar System gravitational physics

NASA Astrophysics Data System (ADS)

Peron, Roberto; Bellettini, G.; Berardi, S.; Boni, A.; Cantone, C.; Coradini, A.; Currie, D. G.; Dell'Agnello, S.; Delle Monache, G. O.; Fiorenza, E.; Garattini, M.; Iafolla, V.; Intaglietta, N.; Lefevre, C.; Lops, C.; March, R.; Martini, M.; Nozzoli, S.; Patrizi, G.; Porcelli, L.; Reale, A.; Santoli, F.; Tauraso, R.; Vittori, R.

2010-05-01

The Solar System is a complex laboratory for testing gravitational physics. Indeed, its scale and hierarchical structure make possible a wide range of tests for gravitational theories, studying the motion of both natural and artificial objects. The usual methodology makes use of tracking information related to the bodies, fitted by a suitable dynamical model. Different equations of motion are provided by different theories, which can be therefore tested and compared. Future exploration scenarios show the possibility of placing deep-space probes near the Sun or in outer Solar System, thereby extending the available experimental data sets. In particular, the Earth-Moon is the most accurately known gravitational three-body laboratory, which is undergoing a new, strong wave of research and exploration (both robotic and manned). In addition, the benefits of a synergetic study of planetary science and gravitational physics are of the greatest importance (as shown by the success of the Apollo program), especially in the Earth-Moon, Mars-Phobos, Jovian and Saturnian sub-suystems. This scenarios open critical issues regarding the quality of the available dynamical models, i.e. their capability of fitting data without an excessive number of empirical hypotheses. A typical case is represented by the non-gravitational phenomena, which in general are difficult to model. More generally, gravitation tests with Lunar Laser Ranging, inner or outer Solar System probes and the appearance of the so-called 'anomalies'(like the one indicated by the Pioneers), whatever their real origin (either instrumental effects or due to new physics), show the necessity of a coordinated improvement of tracking and modelization techniques. A common research path will be discussed, employing the development and use of advanced instrumentation to cope with current limitations of Solar System gravitational tests. In particular, the use of high-sensitivity accelerometers, combined with microwave and laser

NASA's Solar Dynamics Observatory Unveils New Images

NASA Image and Video Library

2010-04-20

Madhulika Guhathakurta, SDO Program Scientist at NASA Headquarters in Washington, speaks during a briefing to discuss recent images from NASA's Solar Dynamics Observatory, or SDO, Wednesday, April 21, 2010, at the Newseum in Washington. Launched on Feb. 11, 2010, SDO is the most advanced spacecraft ever designed to study the sun. During its five-year mission, it will examine the sun's magnetic field and also provide a better understanding of the role the sun plays in Earth's atmospheric chemistry and climate. Photo Credit: (NASA/Carla Cioffi)

Structure and Dynamics of the Solar Corona

NASA Technical Reports Server (NTRS)

Schnack, D. D.

1994-01-01

Advanced computational techniques were used to study solar coronal heating and coronal mass ejections. A three dimensional, time dependent resistive magnetohydrodynamic code was used to study the dynamic response of a model corona to continuous, slow, random magnetic footpoint displacements in the photosphere. Three dimensional numerical simulations of the response of the corona to simple smooth braiding flows in the photosphere were calculated to illustrate and understand the spontaneous formation of current filaments. Two dimensional steady state helmet streamer configurations were obtained by determining the time asymptotic state of the interaction of an initially one dimensinal transponic solar wind with a spherical potential dipole field. The disruption of the steady state helmet streamer configuration was studied as a response to shearing of the magnetic footpoints of the closed field lines under the helmet.

Selection of high temperature thermal energy storage materials for advanced solar dynamic space power systems

NASA Technical Reports Server (NTRS)

Lacy, Dovie E.; Coles-Hamilton, Carolyn; Juhasz, Albert

1987-01-01

Under the direction of NASA's Office of Aeronautics and Technology (OAST), the NASA Lewis Research Center has initiated an in-house thermal energy storage program to identify combinations of phase change thermal energy storage media for use with a Brayton and Stirling Advanced Solar Dynamic (ASD) space power system operating between 1070 and 1400 K. A study has been initiated to determine suitable combinations of thermal energy storage (TES) phase change materials (PCM) that result in the smallest and lightest weight ASD power system possible. To date the heats of fusion of several fluoride salt mixtures with melting points greater than 1025 K have been verified experimentally. The study has indicated that these salt systems produce large ASD systems because of their inherent low thermal conductivity and low density. It is desirable to have PCMs with high densities and high thermal conductivities. Therefore, alternate phase change materials based on metallic alloy systems are also being considered as possible TES candidates for future ASD space power systems.

Advances in Solar Heating and Cooling Systems

ERIC Educational Resources Information Center

Ward, Dan S.

1976-01-01

Reports on technological advancements in the fields of solar collectors, thermal storage systems, and solar heating and cooling systems. Diagrams aid in the understanding of the thermodynamics of the systems. (CP)

Passive Solar still: Recent advancement in design and related Performance.

PubMed

Awasthi, Anuradha; Kumari, Kanchan; Panchal, Hitesh; Sathyamurthy, Ravishankar

2018-05-31

Present review paper mainly focuses on different varieties of solar stills and highlights mostly the passive solar still with advanced modifications in the design and development of material, single and multi-effect solar still with augmentation of different materials, energy absorbing, insulators, mechanisms of heat and mass transfer to improve the loss of heat and enhance the productivity of solar still. The cost-benefit analysis along with the progressive advancement for solar stills is the major highlights of this review. To increase the output of solar still nowadays, applications of advance modifications is one of the promising tools, and it is anticipated that shortly more vigor will be added in this area with the modifications in designs of solar stills.

Advanced In-Space Propulsion: "Exploring the Solar System"

NASA Technical Reports Server (NTRS)

Johnson, Les

2003-01-01

This viewgraph presentation reviews a number of advanced propulsion technologies for interplanetary spacecraft. The objective of the In Space Propulsion Technology Projects Office is to develop in-space propulsion technologies that can enable and/or benefit near and mid-term NASA science missions by significantly reducing cost, mass, and/or travel times. The technologies profiled are divided into several categories: High Priority (aerocapture, next generation ion propulsion, solar sails); Medium Priority (advanced chemical propulsion, solar electric propulsion, Hall thrusters); Low Priority (solar thermal propulsion); and High Payoff/High Risk (1 g/sq m solar sails, momentum exchange tethers, and plasma sails).

NASA's Solar Dynamics Observatory Unveils New Images

NASA Image and Video Library

2010-04-20

Scientists involved in NASA's Solar Dynamics Observatory (SDO) mission attend a press conference to discuss recent images captured by the SDO spacecraft Wednesday, April 21, 2010, at the Newseum in Washington. On Feb. 11, 2010, NASA launched the SDO spacecraft, which is the most advanced spacecraft ever designed to study the sun. Seated left to right are: Dean Pesnell, SDO project scientist, Goddard Space Flight Center in Greenbelt, Md.; Alan Title, principal investigator, Atmospheric Imaging Assembly instrument, Lockheed Martin Solar and Astrophysics Laboratory in Palo Alto; Philip H. Scherrer, principal investigator, Helioseismic and Magnetic Imager instrument, Stanford University in Palo Alto; Tom Woods, principal investigator, Extreme Ultraviolet Variability Experiment Instrument, Laboratory for Atmospheric and Space Physics, University of Colorado in Boulder and Madhulika Guhathakurta, SDO program scientist, NASA Headquarters in Washington. Photo Credit: (NASA/Carla Cioffi)

Solar Dynamics Observatory Artist Concept

NASA Image and Video Library

2010-02-11

The Solar Dynamics Observatory SDO spacecraft, shown above the Earth as it faces toward the Sun. SDO is designed to study the influence of the Sun on the Earth and the inner solar system by studying the solar atmosphere. http://photojournal.jpl.nasa.gov/catalog/PIA18169

Long-Term Dynamics of Small Bodies in the Solar System

NASA Technical Reports Server (NTRS)

Saunders, Steve (Technical Monitor); Holman, Matthew J.

2005-01-01

As part of the NASA Planetary Geology and Geophysics program Prof. Norm Murray (CITA) and I have been conducting investigations of the long-term dynamics of small bodies in the outer solar system. This grant, and its predecessor NAG5-7761, supported travel for collaboration by the Investigators and also supports Murray during an annual one month visit to the CfA for further collaboration. In the course of this grant we made a number of advances in solar system dynamics. For example, we developed an analytic model for the origin and consequence of chaos associated with three-body resonances in the asteroid belt. This has been shown to be important for the delivery of near Earth objects. We later extended this model to three-body resonances among planets. We were able to show that the numerically identified chaos among the outer planets results from a three-body resonance involving Jupiter, Saturn, and Uranus. The resulting paper was awarded the 1999 Newcomb Cleveland award from the AAAS. This award singles out one paper published in Science each year for distinction. This grant has also supported, in part, my participate in other solar system dynamics projects. The results from those collaborations are also listed.

Solar System Dynamics

NASA Technical Reports Server (NTRS)

Wisdom, Jack

2002-01-01

In these 18 years, the research has touched every major dynamical problem in the solar system, including: the effect of chaotic zones on the distribution of asteroids, the delivery of meteorites along chaotic pathways, the chaotic motion of Pluto, the chaotic motion of the outer planets and that of the whole solar system, the delivery of short period comets from the Kuiper belt, the tidal evolution of the Uranian arid Galilean satellites, the chaotic tumbling of Hyperion and other irregular satellites, the large chaotic variations of the obliquity of Mars, the evolution of the Earth-Moon system, and the resonant core- mantle dynamics of Earth and Venus. It has introduced new analytical and numerical tools that are in widespread use. Today, nearly every long-term integration of our solar system, its subsystems, and other solar systems uses algorithms that was invented. This research has all been primarily Supported by this sequence of PGG NASA grants. During this period published major investigations of tidal evolution of the Earth-Moon system and of the passage of the Earth and Venus through non-linear core-mantle resonances were completed. It has published a major innovation in symplectic algorithms: the symplectic corrector. A paper was completed on non-perturbative hydrostatic equilibrium.

Identification of salt-alloy combinations for thermal energy storage applications in advanced solar dynamic power systems

NASA Technical Reports Server (NTRS)

Whittenberger, J. D.; Misra, A. K.

1987-01-01

Thermodynamic calculations based on the available data for flouride salt systems reveal that a number of congruently melting compositions and eutectics exist which have the potential to meet the lightweight, high energy storage requirements imposed for advanced solar dynamic systems operating between about 1000 and 1400 K. Compatibility studies to determine suitable containment alloys to be used with NaF-22CaF2-13MgF2, NaF-32CaF2, and NaF-23MgF2 have been conducted at the eutectic temperature + 25 K for each system. For these three NaF-based eutectics, none of the common, commercially available high temperature alloys appear to offer adequate corrosion resistance for a long lifetime; however mild steel, pure nickel and Nb-1Zr could prove useful. These latter materials suggest the possibility that a strong, corrosion resistant, nonrefractory, elevated temperature alloy based on the Ni-Ni3Nb system could be developed.

Advanced photovoltaic solar array development

NASA Technical Reports Server (NTRS)

Kurland, Richard M.; Stella, Paul

1989-01-01

Phase 2 of the Advanced Photovoltaic Solar Array (APSA) program, started in mid-1987, is currently in progress to fabricate prototype wing hardware that will lead to wing integration and testing in 1989. The design configuration and key details are reviewed. A status of prototype hardware fabricated to date is provided. Results from key component-level tests are discussed. Revised estimates of array-level performance as a function of solar cell device technology for geosynchronous missions are given.

Advanced photovoltaic solar array design assessment

NASA Technical Reports Server (NTRS)

Stella, Paul; Scott-Monck, John

1987-01-01

The Advanced Photovoltaic Solar Array (APSA) program seeks to bring to flight readiness a solar array that effectively doubles the specific power of the Solar Array Flight Experiment/Solar Electric Propulsion (SAFE/SEP) design that was successfully demonstrated during the Shuttle 41-D mission. APSA is a critical intermediate milestone in the effort to demonstrate solar array technologies capable of 300 W/kg and 300 W/square m at beginning of life (BOL). It is not unreasonable to anticipate the development of solar array designs capable of 300 W/kg at BOL for operational power levels approx. greater than 25 kW sub e. It is also quite reasonable to expect that high performance solar arrays capable of providing at least 200 W/kg at end of life for most orbits now being considered by mission planners will be realized in the next decade.

Projected techno-economic improvements for advanced solar thermal power plants

NASA Technical Reports Server (NTRS)

Fujita, T.; Manvi, R.; Roschke, E. J.

1979-01-01

The projected characteristics of solar thermal power plants (with outputs up to 10 MWe) employing promising advanced technology subsystems/components are compared to current (or pre-1985) steam-Rankine systems. Improvements accruing to advanced technology development options are delineated. The improvements derived from advanced systems result primarily from achieving high efficiencies via solar collector systems which (1) capture a large portion of the available insolation and (2) concentrate this captured solar flux to attain high temperatures required for high heat engine/energy conversion performance. The most efficient solar collector systems employ two-axis tracking. Attractive systems include the central receiver/heliostat and the parabolic dish.

Long-Term Dynamics of Small Bodies in the Solar System

NASA Technical Reports Server (NTRS)

Holman, Matthew J.; Grant, John (Technical Monitor)

2002-01-01

As part of the NASA Planetary Geology and Geophysics program, Prof. Norm Murray (CITA (Canadian Institute of Theoretical Astrophysics)) and I have been conducting investigations of the long-term dynamics of small bodies in the outer solar system. This grant, and its successor NAG5-10365, supports travel for collaboration by the Investigators and also supports Murray during an annual one month visit to the CfA (Harvard-Smithsonian Center for Astrophysics) for further collaboration. In the course of this grant we made a number of advances in solar system dynamics. For example, we developed an analytic model for the origin and consequence of chaos associated with three-body resonances in the asteroid belt. This has been shown to be important for the delivery of near Earth objects (NEO). We later extended this model to three-body resonances among planets. We were able to show that the numerically identified chaos among the outer planets results from a three-body resonance involving Jupiter, Saturn, and Uranus. The resulting paper was awarded the 1999 Newcomb Cleveland award from the AAAS (American Association for the Advancement of Science). This award singles out one paper published in Science each year for distinction. A list of grant-related publications is presented, with abstracts included.

Solar Dynamics Observatory Briefing

NASA Image and Video Library

2010-01-21

Madhulika Guhathakurta, SDO Program Scientist, speaks during a briefing to discuss the upcoming launch of NASA's Solar Dynamic Observatory, or SDO, Thursday, Jan. 21, 2010, at NASA Headquarters in Washington. The mission is to study the Sun and its dynamic behavior. Photo Credit: (NASA/Paul E. Alers)

Recent advances of flexible hybrid perovskite solar cells

NASA Astrophysics Data System (ADS)

Shin, Dong Hee; Heo, Jin Hyuck; Im, Sang Hyuk

2017-11-01

Recently, hybrid perovskite solar cells have attracted great interest because they can be fabricated to low cost, flexible, and highly efficient solar cells. Here, we introduced recent advances of flexible hybrid perovskite solar cells. We introduced research background of flexible perovskite solar cells in introduction part. Then we composed the main body to i) structure and properties of hybrid perovskite solar cells, ii) why flexible hybrid perovskite solar cells are important?, iii) transparent conducting oxide (TCO) based flexible hybrid perovskite solar cells, and iv) TCO-free transparent conducting electrode (TCE) based flexible hybrid perovskite solar cells. Finally, we summarized research outlook of flexible hybrid perovskite solar cells.

NASA's Solar Dynamics Observatory Unveils New Images

NASA Image and Video Library

2010-04-20

Alan Title, second from left, principal investigator, Atmospheric Imaging Assembly instrument, Lockheed Martin Solar and Astrophysics Laboratory in Palo Alto, speaks during a briefing to discuss recent images from NASA's Solar Dynamics Observatory, or SDO, Wednesday, April 21, 2010, at the Newseum in Washington. Launched on Feb. 11, 2010, SDO is the most advanced spacecraft ever designed to study the sun. During its five-year mission, it will examine the sun's magnetic field and also provide a better understanding of the role the sun plays in Earth's atmospheric chemistry and climate. Pictured from left to right: Dean Pesnell, SDO project scientist, Goddard Space Flight Center in Greenbelt, Md., Alan Title, Philip H. Scherrer, principal investigator, Helioseismic and Magnetic Imager instrument, Stanford University in Palo Alto, Tom Woods, principal investigator, Extreme Ultraviolet Variability Experiment instrument, Laboratory for Atmospheric and Space Physics, University of Colorado in Boulder and Madhulika Guhathakurta, SDO program scientist, NASA Headquarters in Washington. Photo Credit: (NASA/Carla Cioffi)

NREL Projects Awarded More Than $3 Million to Advance Novel Solar

Science.gov Websites

in Grid Operations," evaluating a research solution to better integrate solar power generation funding program, which advances state-of-the-art techniques for predicting solar power generation to Office to advance predictive modeling of solar power as part of its Solar Forecasting 2 funding program

A large-scale solar dynamics observatory image dataset for computer vision applications.

PubMed

Kucuk, Ahmet; Banda, Juan M; Angryk, Rafal A

2017-01-01

The National Aeronautics Space Agency (NASA) Solar Dynamics Observatory (SDO) mission has given us unprecedented insight into the Sun's activity. By capturing approximately 70,000 images a day, this mission has created one of the richest and biggest repositories of solar image data available to mankind. With such massive amounts of information, researchers have been able to produce great advances in detecting solar events. In this resource, we compile SDO solar data into a single repository in order to provide the computer vision community with a standardized and curated large-scale dataset of several hundred thousand solar events found on high resolution solar images. This publicly available resource, along with the generation source code, will accelerate computer vision research on NASA's solar image data by reducing the amount of time spent performing data acquisition and curation from the multiple sources we have compiled. By improving the quality of the data with thorough curation, we anticipate a wider adoption and interest from the computer vision to the solar physics community.

Advanced solar panel designs

NASA Technical Reports Server (NTRS)

Ralph, E. L.; Linder, E. B.

1996-01-01

Solar panel designs that utilize new high-efficiency solar cells and lightweight rigid panel technologies are described. The resulting designs increase the specific power (W/kg) achievable in the near-term and are well suited to meet the demands of higher performance small satellites (smallsats). Advanced solar panel designs have been developed and demonstrated on two NASA SBIR contracts at Applied Solar. The first used 19% efficient, large area (5.5 cm x 6.5 cm) GaAs/Ge solar cells with a lightweight rigid graphite epoxy isogrid substrate configuration. A 1,445 cm(exp 2) coupon was fabricated and tested to demonstrate 60 W/kg with a high potential of achieving 80 W/kg. The second panel design used new 22% efficiency, dual junction GaInP2/GaAs/Ge solar cells combined with a lightweight aluminum core/graphite fiber mesh facesheet substrate. A 1,445 cm(exp 2) coupon was fabricated and tested to demonstrate 105 W/kg with the potential of achieving 115 W/kg. This paper will address the construction details for the GaAs/isogrid and dual-junction GaAs/carbon mesh panel configurations. These are ultimately sized to provide 75 Watts and 119 Watts respectively for smallsats or may be used as modular building blocks for larger systems. GaAs/isogrid and dual-junction GaAs/carbon mesh coupons have been fabricated and tested to successfully demonstrate critical performance parameters and results are also provided here.

Advanced Solar Cells for Satellite Power Systems

NASA Technical Reports Server (NTRS)

Flood, Dennis J.; Weinberg, Irving

1994-01-01

The multiple natures of today's space missions with regard to operational lifetime, orbital environment, cost and size of spacecraft, to name just a few, present such a broad range of performance requirements to be met by the solar array that no single design can suffice to meet them all. The result is a demand for development of specialized solar cell types that help to optimize overall satellite performance within a specified cost range for any given space mission. Historically, space solar array performance has been optimized for a given mission by tailoring the features of silicon solar cells to account for the orbital environment and average operating conditions expected during the mission. It has become necessary to turn to entirely new photovoltaic materials and device designs to meet the requirements of future missions, both in the near and far term. This paper will outline some of the mission drivers and resulting performance requirements that must be met by advanced solar cells, and provide an overview of some of the advanced cell technologies under development to meet them. The discussion will include high efficiency, radiation hard single junction cells; monolithic and mechanically stacked multiple bandgap cells; and thin film cells.

Advanced solar cells for satellite power systems

NASA Astrophysics Data System (ADS)

Flood, Dennis J.; Weinberg, Irving

1994-11-01

The multiple natures of today's space missions with regard to operational lifetime, orbital environment, cost and size of spacecraft, to name just a few, present such a broad range of performance requirements to be met by the solar array that no single design can suffice to meet them all. The result is a demand for development of specialized solar cell types that help to optimize overall satellite performance within a specified cost range for any given space mission. Historically, space solar array performance has been optimized for a given mission by tailoring the features of silicon solar cells to account for the orbital environment and average operating conditions expected during the mission. It has become necessary to turn to entirely new photovoltaic materials and device designs to meet the requirements of future missions, both in the near and far term. This paper will outline some of the mission drivers and resulting performance requirements that must be met by advanced solar cells, and provide an overview of some of the advanced cell technologies under development to meet them. The discussion will include high efficiency, radiation hard single junction cells; monolithic and mechanically stacked multiple bandgap cells; and thin film cells.

Solar Dynamics Observatory Briefing

NASA Image and Video Library

2010-01-21

Richard Fisher, Heliophysics Division Director at NASA Headquarters, speaks during a briefing to discuss the upcoming launch of NASA's Solar Dynamic Observatory, or SDO, Thursday, Jan. 21, 2010, at NASA Headquarters in Washington. The mission is to study the Sun and its dynamic behavior. Photo Credit: (NASA/Paul E. Alers)

Solar dynamic power system development for Space Station Freedom

NASA Technical Reports Server (NTRS)

1993-01-01

The development of a solar dynamic electric power generation system as part of the Space Station Freedom Program is documented. The solar dynamic power system includes a solar concentrator, which collects sunlight; a receiver, which accepts and stores the concentrated solar energy and transfers this energy to a gas; a Brayton turbine, alternator, and compressor unit, which generates electric power; and a radiator, which rejects waste heat. Solar dynamic systems have greater efficiency and lower maintenance costs than photovoltaic systems and are being considered for future growth of Space Station Freedom. Solar dynamic development managed by the NASA Lewis Research Center from 1986 to Feb. 1991 is covered. It summarizes technology and hardware development, describes 'lessons learned', and, through an extensive bibliography, serves as a source list of documents that provide details of the design and analytic results achieved. It was prepared by the staff of the Solar Dynamic Power System Branch at the NASA Lewis Research Center in Cleveland, Ohio. The report includes results from the prime contractor as well as from in-house efforts, university grants, and other contracts. Also included are the writers' opinions on the best way to proceed technically and programmatically with solar dynamic efforts in the future, on the basis of their experiences in this program.

Advanced Solar Power Systems

NASA Technical Reports Server (NTRS)

Atkinson, J. H.; Hobgood, J. M.

1984-01-01

The Advanced Solar Power System (ASPS) concentrator uses a technically sophisticated design and extensive tooling to produce very efficient (80 to 90%) and versatile energy supply equipment which is inexpensive to manufacture and requires little maintenance. The advanced optical design has two 10th order, generalized aspheric surfaces in a Cassegrainian configuration which gives outstanding performance and is relatively insensitive to temperature changes and wind loading. Manufacturing tolerances also have been achieved. The key to the ASPS is the direct absorption of concentrated sunlight in the working fluid by radiative transfers in a black body cavity. The basic ASPS design concepts, efficiency, optical system, and tracking and focusing controls are described.

Solar Dynamics Observatory Briefing

NASA Image and Video Library

2010-01-21

Richard Fisher, Heliophysics Division Director at NASA Headquarters, left, speaks during a briefing to discuss the upcoming launch of NASA's Solar Dynamic Observatory, or SDO, Thursday, Jan. 21, 2010, as Madhulika Guhathakurta, SDO Program Scientist looks on at NASA Headquarters in Washington. The mission is to study the Sun and its dynamic behavior. Photo Credit: (NASA/Paul E. Alers)

The Implementation of Advanced Solar Array Technology in Future NASA Missions

NASA Technical Reports Server (NTRS)

Piszczor, Michael F.; Kerslake, Thomas W.; Hoffman, David J.; White, Steve; Douglas, Mark; Spence, Brian; Jones, P. Alan

2003-01-01

Advanced solar array technology is expected to be critical in achieving the mission goals on many future NASA space flight programs. Current PV cell development programs offer significant potential and performance improvements. However, in order to achieve the performance improvements promised by these devices, new solar array structures must be designed and developed to accommodate these new PV cell technologies. This paper will address the use of advanced solar array technology in future NASA space missions and specifically look at how newer solar cell technologies impact solar array designs and overall power system performance.

Advanced reflector materials for solar concentrators

NASA Astrophysics Data System (ADS)

Jorgensen, Gary; Williams, Tom; Wendelin, Tim

1994-10-01

This paper describes the research and development at the US National Renewable Energy Laboratory (NREL) in advanced reflector materials for solar concentrators. NREL's research thrust is to develop solar reflector materials that maintain high specular reflectance for extended lifetimes under outdoor service conditions and whose cost is significantly lower than existing products. Much of this work has been in collaboration with private-sector companies that have extensive expertise in vacuum-coating and polymer-film technologies. Significant progress and other promising developments will be discussed. These are expected to lead to additional improvements needed to commercialize solar thermal concentration systems and make them economically attractive to the solar manufacturing industry. To explicitly demonstrate the optical durability of candidate reflector materials in real-world service conditions, a network of instrumented outdoor exposure sites has been activated.

Technology development program for an advanced microsheet glass concentrator

NASA Technical Reports Server (NTRS)

Richter, Scott W.; Lacy, Dovie E.

1990-01-01

Solar Dynamic Space Power Systems are candidate electrical power generating systems for future NASA missions. One of the key components in a solar dynamic power system is the concentrator which collects the sun's energy and focuses it into a receiver. In 1985, the NASA Lewis Research Center initiated the Advanced Solar Dynamic Concentrator Program with funding from NASA's Office of Aeronautics and Space Technology (OAST). The objectives of the Advanced Concentrator Program is to develop the technology that will lead to lightweight, highly reflective, accurate, scaleable, and long lived (7 to 10 years) space solar dynamic concentrators. The Advanced Concentrator Program encompasses new and innovative concepts, fabrication techniques, materials selection, and simulated space environmental testing. The Advanced Microsheet Glass Concentrator Program, a reflector concept, that is currently being investigated both in-house and under contract is discussed.

Modeling and Flight Data Analysis of Spacecraft Dynamics with a Large Solar Array Paddle

NASA Technical Reports Server (NTRS)

Iwata, Takanori; Maeda, Ken; Hoshino, Hiroki

2007-01-01

The Advanced Land Observing Satellite (ALOS) was launched on January 24 2006 and has been operated successfully since then. This satellite has the attitude dynamics characterized by three large flexible structures, four large moving components, and stringent attitude/pointing stability requirements. In particular, it has one of the largest solar array paddles. Presented in this paper are flight data analyses and modeling of spacecraft attitude motion induced by the large solar array paddle. On orbit attitude dynamics was first characterized and summarized. These characteristic motions associated with the solar array paddle were identified and assessed. These motions are thermally induced motion, the pitch excitation by the paddle drive, and the role excitation. The thermally induced motion and the pitch excitation by the paddle drive were modeled and simulated to verify the mechanics of the motions. The control law updates implemented to mitigate the attitude vibrations are also reported.

Early Results from Solar Dynamic Space Power System Testing

NASA Technical Reports Server (NTRS)

Shaltens, Richard K.; Mason, Lee S.

1996-01-01

A government/industry team designed, built and tested a 2-kWe solar dynamic space power system in a large thermal vacuum facility with a simulated Sun at the NASA Lewis Research Center. The Lewis facility provides an accurate simulation of temperatures, high vacuum and solar flux as encountered in low-Earth orbit. The solar dynamic system includes a Brayton power conversion unit integrated with a solar receiver which is designed to store energy for continuous power operation during the eclipse phase of the orbit. This paper reviews the goals and status of the Solar Dynamic Ground Test Demonstration project and describes the initial testing, including both operational and performance data. System testing to date has accumulated over 365 hours of power operation (ranging from 400 watts to 2.0-W(sub e)), including 187 simulated orbits, 16 ambient starts and 2 hot restarts. Data are shown for an orbital startup, transient and steady-state orbital operation and shutdown. System testing with varying insolation levels and operating speeds is discussed. The solar dynamic ground test demonstration is providing the experience and confidence toward a successful flight demonstration of the solar dynamic technologies on the Space Station Mir in 1997.

Research opportunities to advance solar energy utilization.

PubMed

Lewis, Nathan S

2016-01-22

Major developments, as well as remaining challenges and the associated research opportunities, are evaluated for three technologically distinct approaches to solar energy utilization: solar electricity, solar thermal, and solar fuels technologies. Much progress has been made, but research opportunities are still present for all approaches. Both evolutionary and revolutionary technology development, involving foundational research, applied research, learning by doing, demonstration projects, and deployment at scale will be needed to continue this technology-innovation ecosystem. Most of the approaches still offer the potential to provide much higher efficiencies, much lower costs, improved scalability, and new functionality, relative to the embodiments of solar energy-conversion systems that have been developed to date. Copyright © 2016, American Association for the Advancement of Science.

Third Advances in Solar Physics Euroconference: Magnetic Fields and Oscillations

NASA Astrophysics Data System (ADS)

Schmieder, B.; Hofmann, A.; Staude, J.

The third Advances in Solar Physics Euroconference (ASPE) "Magnetic Fields and Oscillations"concluded a series of three Euroconferences sponsored by the European Union. The meeting took place in Caputh near Potsdam, Germany, on September 22-25, 1998, followed by the JOSO (Joint Organization for Solar Observations) 30th Annual Board Meeting on September 26, 1998. The ASPE formula is attractive and compares well with other meetings with "show-and-tell" character. This meeting had 122 participants coming from 26 countries; 36 participants came from countries formerly behind the Iron Curtain; a "politically incorrect" estimate says that 48 participants were below 35 years of age, with an unusually large female-to-male ratio. This characteristic of youngness is the more striking since solar physics is a perhaps overly established field exhibiting an overly senior age profile. It was a good opportunity to train this young generation in Solar Physics. The conference topic "Magnetic Fields and Oscillations" obviously was wide enough to cater to many an interest. These proceedings are organized according to the structure of the meeting. They include the topics 'High resolution spectropolarimetry and magnetometry', 'Flux-tube dynamics', 'Modelling of the 3-D magnetic field structure', 'Mass motions and magnetic fields in sunspot penumbral structures', 'Sunspot oscillations', 'Oscillations in active regions - diagnostics and seismology', 'Network and intranetwork structure and dynamics', and 'Waves in magnetic structures'. These topics covered the first 2.5 days of the conference. The reviews, oral contributions, and poster presentations were by no means all of the meeting. The ASPE formula also adds extensive plenary sessions of JOSO Working groups on topics that involve planning of Europe-wide collaboration. At this meeting these concerned solar observing techniques, solar data bases, coordination between SOHO and ground-based observing, and preparations for August 11, 1999

Solar concentrator advanced development project

NASA Technical Reports Server (NTRS)

Corrigan, Robert D.; Ehresman, Derik T.

1987-01-01

A solar dynamic concentrator design developed for use with a solar-thermodynamic power generation module intended for the Space Station is considered. The truss hexagonal panel reflector uses a modular design approach and is flexible in attainable flux profiles and assembly techniques. Preliminary structural, thermal, and optical analysis results are discussed. Accuracy of the surface reflectors should be within 5 mrad rms slope error, resulting in the need for close fabrication tolerances. Significant fabrication issues to be addressed include the facet reflective and protective coating processes and the surface specularity requirements.

The "Sigmoid Sniffer” and the "Advanced Automated Solar Filament Detection and Characterization Code” Modules

NASA Astrophysics Data System (ADS)

Raouafi, Noureddine; Bernasconi, P. N.; Georgoulis, M. K.

2010-05-01

We present two pattern recognition algorithms, the "Sigmoid Sniffer” and the "Advanced Automated Solar Filament Detection and Characterization Code,” that are among the Feature Finding modules of the Solar Dynamic Observatory: 1) Coronal sigmoids visible in X-rays and the EUV are the result of highly twisted magnetic fields. They can occur anywhere on the solar disk and are closely related to solar eruptive activity (e.g., flares, CMEs). Their appearance is typically synonym of imminent solar eruptions, so they can serve as a tool to forecast solar activity. Automatic X-ray sigmoid identification offers an unbiased way of detecting short-to-mid term CME precursors. The "Sigmoid Sniffer” module is capable of automatically detecting sigmoids in full-disk X-ray images and determining their chirality, as well as other characteristics. It uses multiple thresholds to identify persistent bright structures on a full-disk X-ray image of the Sun. We plan to apply the code to X-ray images from Hinode/XRT, as well as on SDO/AIA images. When implemented in a near real-time environment, the Sigmoid Sniffer could allow 3-7 day forecasts of CMEs and their potential to cause major geomagnetic storms. 2)The "Advanced Automated Solar Filament Detection and Characterization Code” aims to identify, classify, and track solar filaments in full-disk Hα images. The code can reliably identify filaments; determine their chirality and other relevant parameters like filament area, length, and average orientation with respect to the equator. It is also capable of tracking the day-by-day evolution of filaments as they traverse the visible disk. The code was tested by analyzing daily Hα images taken at the Big Bear Solar Observatory from mid-2000 to early-2005. It identified and established the chirality of thousands of filaments without human intervention.

Advancing solar energy forecasting through the underlying physics

NASA Astrophysics Data System (ADS)

Yang, H.; Ghonima, M. S.; Zhong, X.; Ozge, B.; Kurtz, B.; Wu, E.; Mejia, F. A.; Zamora, M.; Wang, G.; Clemesha, R.; Norris, J. R.; Heus, T.; Kleissl, J. P.

2017-12-01

As solar power comprises an increasingly large portion of the energy generation mix, the ability to accurately forecast solar photovoltaic generation becomes increasingly important. Due to the variability of solar power caused by cloud cover, knowledge of both the magnitude and timing of expected solar power production ahead of time facilitates the integration of solar power onto the electric grid by reducing electricity generation from traditional ancillary generators such as gas and oil power plants, as well as decreasing the ramping of all generators, reducing start and shutdown costs, and minimizing solar power curtailment, thereby providing annual economic value. The time scales involved in both the energy markets and solar variability range from intra-hour to several days ahead. This wide range of time horizons led to the development of a multitude of techniques, with each offering unique advantages in specific applications. For example, sky imagery provides site-specific forecasts on the minute-scale. Statistical techniques including machine learning algorithms are commonly used in the intra-day forecast horizon for regional applications, while numerical weather prediction models can provide mesoscale forecasts on both the intra-day and days-ahead time scale. This talk will provide an overview of the challenges unique to each technique and highlight the advances in their ongoing development which come alongside advances in the fundamental physics underneath.

Long-Term Dynamics of Small Bodies in the Solar System

NASA Technical Reports Server (NTRS)

Holman, Matthew J.

2004-01-01

As part of the NASA Planetary Geology and Geophysics program Prof. Norm Murray (CITA) and I have been conducting investigations of the long-term dynamics of small bodies in the outer solar system. This grant, and its predecessor NAG5- 7761, supports travel for collaboration by the Investigators and also supports Murray during an annual one month visit to the CfA for further collaboration. In the course of this grant we made a number of advances in solar system dynamics. For example, we developed an analytic model for the origin and consequence of chaos associated with three-body resonances in the asteroid belt. This has been shown to be important for the delivery of near Earth objects. We later extended this model to three- body resonances among planets. We were able to show that the numerically identified chaos among the outer planets results from a three-body resonance involving Jupiter, Saturn, and Uranus. The resulting paper was awarded the 1999 Newcomb Cleveland award from the AAAS. This award singles out one paper published in Science each year for distinction.

Recent Progress in Heliogyro Solar Sail Structural Dynamics

NASA Technical Reports Server (NTRS)

Wilkie, William K.; Warren, Jerry E.; Horta, Lucas G.; Juang, Jer-Nan; Gibbs, Samuel C.; Dowell, E.; Guerrant, Daniel; Lawrence Dale

2014-01-01

Results from recent National Aeronautics and Space Administration (NASA) research on the structural dynamics and control characteristics of heliogyro solar sails are summarized. Specific areas under investigation include coupled nonlinear finite element analysis of heliogyro membrane blade with solar radiation pressure effects, system identification of spinning membrane structures, solarelastic stability analysis of heliogyro solar sails, including stability during blade deployment, and results from small-scale in vacuo dynamics experiments with spinning high-aspect ratio membranes. A low-cost, rideshare payload heliogyro technology demonstration mission concept, used as a mission context for these heliogyro structural dynamics and solarelasticity investigations, is also described.

Solar dynamic power systems for space station

NASA Technical Reports Server (NTRS)

Irvine, Thomas B.; Nall, Marsha M.; Seidel, Robert C.

1986-01-01

The Parabolic Offset Linearly Actuated Reflector (POLAR) solar dynamic module was selected as the baseline design for a solar dynamic power system aboard the space station. The POLAR concept was chosen over other candidate designs after extensive trade studies. The primary advantages of the POLAR concept are the low mass moment of inertia of the module about the transverse boom and the compactness of the stowed module which enables packaging of two complete modules in the Shuttle orbiter payload bay. The fine pointing control system required for the solar dynamic module has been studied and initial results indicate that if disturbances from the station are allowed to back drive the rotary alpha joint, pointing errors caused by transient loads on the space station can be minimized. This would allow pointing controls to operate in bandwidths near system structural frequencies. The incorporation of the fine pointing control system into the solar dynamic module is fairly straightforward for the three strut concentrator support structure. However, results of structural analyses indicate that this three strut support is not optimum. Incorporation of a vernier pointing system into the proposed six strut support structure is being studied.

Advanced heat receiver conceptual design study

NASA Technical Reports Server (NTRS)

Kesseli, James; Saunders, Roger; Batchelder, Gary

1988-01-01

Solar Dynamic space power systems are candidate electrical power generating systems for future NASA missions. One of the key components of the solar dynamic power system is the solar receiver/thermal energy storage (TES) subsystem. Receiver development was conducted by NASA in the late 1960's and since then a very limited amount of work has been done in this area. Consequently the state of the art (SOA) receivers designed for the IOC space station are large and massive. The objective of the Advanced Heat Receiver Conceptual Design Study is to conceive and analyze advanced high temperature solar dynamic Brayton and Stirling receivers. The goal is to generate innovative receiver concepts that are half of the mass, smaller, and more efficient than the SOA. It is also necessary that these innovative receivers offer ease of manufacturing, less structural complexity and fewer thermal stress problems. Advanced Brayton and Stirling receiver storage units are proposed and analyzed in this study which can potentially meet these goals.

Advancements in solar stills for enhanced flow rate

NASA Astrophysics Data System (ADS)

Mishra, Sourav; Dubey, Maneesh; Raghuwanshi, Jitendra; Sharma, Vipin

2018-05-01

All over the world there is a scarcity of water and it is difficult to access potable water. Due to this most of the people are affected by diseases that are caused due to drinking of polluted water. There are technologies through which we can purify polluted water but the only problem is these technologies uses electrical energy. Since solar energy is abundant in nature therefore we can use solar as an energy source in solar stills for water distillation. Solar stills can be used in village areas where there is no electricity. It is simple and also economic in construction. This article addresses advancement in solar distillation and usage of nanofluids for enhancement in flow rate.

Quasi-steady solar wind dynamics

NASA Technical Reports Server (NTRS)

Pizzo, V. J.

1983-01-01

Progress in understanding the large scale dynamics of quasisteady, corotating solar wind structure was reviewed. The nature of the solar wind at large heliocentric distances preliminary calculations from a 2-D MHD model are used to demonstrate theoretical expectations of corotating structure out to 30 AU. It is found that the forward and reverse shocks from adjacent CIR's begin to interact at about 10 AU, producing new shock pairs flanking secondary CIR's. These sawtooth secondary CIR's interact again at about 20 AU and survive as visible entities to 30 AU. The model predicts the velocity jumps at the leading edge of the secondary CIR's at 30 AU should be very small but there should still be sizable variations in the thermodynamic and magnetic parameters. The driving dynamic mechanism in the distant solar wind is the relaxation of pressure gradients. The second topic is the influence of weak, nonimpulsive time dependence in quasisteady dynamics. It is suggested that modest large scale variations in the coronal flow speed on periods of several hours to a day may be responsible for many of the remaining discrepancies between theory and observation. Effects offer a ready explanation for the apparent rounding of stream fronts between 0.3 and 1.0 AU discovered by Helios.

Operational considerations of the Advanced Photovoltaic Solar Array

NASA Technical Reports Server (NTRS)

Stella, Paul M.; Kurland, Richard M.

1992-01-01

Issues affecting the long-term operational performance of the Advanced Photovoltaic Solar Array (APSA) are discussed, with particular attention given to circuit electrical integrity from shadowed and cracked cell modules. The successful integration of individual advanced array components provides a doubling of array specific performance from the previous NASA-developed advanced array (SAFE). Flight test modules both recently fabricated and under fabrication are described. The development of advanced high-performance blanket technology for future APSA enhancement is presented.

Operational considerations of the Advanced Photovoltaic Solar Array

NASA Astrophysics Data System (ADS)

Stella, Paul M.; Kurland, Richard M.

Issues affecting the long-term operational performance of the Advanced Photovoltaic Solar Array (APSA) are discussed, with particular attention given to circuit electrical integrity from shadowed and cracked cell modules. The successful integration of individual advanced array components provides a doubling of array specific performance from the previous NASA-developed advanced array (SAFE). Flight test modules both recently fabricated and under fabrication are described. The development of advanced high-performance blanket technology for future APSA enhancement is presented.

Advanced Photovoltaic Solar Array program status

NASA Technical Reports Server (NTRS)

Kurland, Richard M.; Stella, Paul M.

1989-01-01

The Advanced Photolvoltaic Solar Array (APSA) Program is discussed. The objective of the program is to demonstrate a producible array system by the end of this decade with a beginning-of-life (BOL) specific power of 130 W/kg at 10 kW as an intermediate milestone toward the ultimate goal of 300 W/kg at 25 kW by the year 2000. The near-term goal represents a significant improvement over existing rigid panel flight arrays (25 to 45 W/kg) and the first-generation flexible blanket NASA/OAST SAFE I array of the early 1980s, which was projected to provide about 60 W/kg BOL. The prototype wing hardware is in the last stages of fabrication and integration. The current status of the program is reported. The array configuration and key design details are shown. Projections are shown for future performance enhancements that may be expected through the use of advanced structural components and solar cells.

Report from solar physics

NASA Technical Reports Server (NTRS)

Walker, A. B. C.; Acton, L.; Brueckner, G.; Chupp, E. L.; Hudson, H. S.; Roberts, W.

1989-01-01

A discussion of the nature of solar physics is followed by a brief review of recent advances in the field. These advances include: the first direct experimental confirmation of the central role played by thermonuclear processes in stars; the discovery that the 5-minute oscillations of the Sun are a global seismic phenomenon that can be used as a probe of the structure and dynamical behavior of the solar interior; the discovery that the solar magnetic field is subdivided into individual flux tubes with field strength exceeding 1000 gauss. Also covered was a science strategy for pure solar physics. Brief discussions are given of solar-terrestrial physics, solar/stellar relationships, and suggested space missions.

Latest developments in the Advanced Photovoltaic Solar Array Program

NASA Technical Reports Server (NTRS)

Stella, Paul M.; Kurland, Richard M.

1990-01-01

In 1985, the Advanced Photovoltaic Solar Array (APSA) Program was established to demonstrate a producible array system with a specific power greater than 130 W/kg at a 10-kW (BOL) power level. The latest program phase completed fabrication and initial functional testing of a prototype wing representative of a full-scale 5-kW (BOL) wing (except truncated in length to about 1 kW), with weight characteristics that could meet the 130-W/kg (BOL) specific power goal using thin silicon solar cell modules and weight-efficient structural components. The wing configuration and key design details are reviewed, along with results from key component-level and wing-level tests. Projections for future enhancements that may be expected through the use of advanced solar cells and structural components are shown. Performance estimates are given for solar electric propulsion orbital transfer missions through the Van Allen radiation belts. The latest APSA program plans are presented.

A heat receiver design for solar dynamic space power systems

NASA Technical Reports Server (NTRS)

Baker, Karl W.; Dustin, Miles O.; Crane, Roger

1990-01-01

An advanced heat pipe receiver designed for a solar dynamic space power system is described. The power system consists of a solar concentrator, solar heat receiver, Stirling heat engine, linear alternator and waste heat radiator. The solar concentrator focuses the sun's energy into a heat receiver. The engine and alternator convert a portion of this energy to electric power and the remaining heat is rejected by a waste heat radiator. Primary liquid metal heat pipes transport heat energy to the Stirling engine. Thermal energy storage allows this power system to operate during the shade portion of an orbit. Lithium fluoride/calcium fluoride eutectic is the thermal energy storage material. Thermal energy storage canisters are attached to the midsection of each heat pipe. The primary heat pipes pass through a secondary vapor cavity heat pipe near the engine and receiver interface. The secondary vapor cavity heat pipe serves three important functions. First, it smooths out hot spots in the solar cavity and provides even distribution of heat to the engine. Second, the event of a heat pipe failure, the secondary heat pipe cavity can efficiently transfer heat from other operating primary heat pipes to the engine heat exchanger of the defunct heat pipe. Third, the secondary heat pipe vapor cavity reduces temperature drops caused by heat flow into the engine. This unique design provides a high level of reliability and performance.

Advanced solar panel designs

NASA Technical Reports Server (NTRS)

Ralph, E. L.; Linder, E.

1995-01-01

This paper describes solar cell panel designs that utilize new hgih efficiency solar cells along with lightweight rigid panel technology. The resulting designs push the W/kg and W/sq m parameters to new high levels. These new designs are well suited to meet the demand for higher performance small satellites. This paper reports on progress made on two SBIR Phase 1 contracts. One panel design involved the use of large area (5.5 cm x 6.5 cm) GaAs/Ge solar cells of 19% efficiency combined with a lightweight rigid graphite fiber epoxy isogrid substrate configuration. A coupon (38 cm x 38 cm) was fabricated and tested which demonstrated an array specific power level of 60 W/kg with a potential of reaching 80 W/kg. The second panel design involved the use of newly developed high efficiency (22%) dual junction GaInP2/GaAs/Ge solar cells combined with an advanced lightweight rigid substrate using aluminum honeycomb core with high strength graphite fiber mesh facesheets. A coupon (38 cm x 38 cm) was fabricated and tested which demonstrated an array specific power of 105 W/kg and 230 W/sq m. This paper will address the construction details of the panels and an a analysis of the component weights. A strawman array design suitable for a typical small-sat mission is described for each of the two panel design technologies being studied. Benefits in respect to weight reduction, area reduction, and system cost reduction are analyzed and compared to conventional arrays.

Dynamic Modeling of Solar Dynamic Components and Systems

NASA Technical Reports Server (NTRS)

Hochstein, John I.; Korakianitis, T.

1992-01-01

The purpose of this grant was to support NASA in modeling efforts to predict the transient dynamic and thermodynamic response of the space station solar dynamic power generation system. In order to meet the initial schedule requirement of providing results in time to support installation of the system as part of the initial phase of space station, early efforts were executed with alacrity and often in parallel. Initially, methods to predict the transient response of a Rankine as well as a Brayton cycle were developed. Review of preliminary design concepts led NASA to select a regenerative gas-turbine cycle using a helium-xenon mixture as the working fluid and, from that point forward, the modeling effort focused exclusively on that system. Although initial project planning called for a three year period of performance, revised NASA schedules moved system installation to later and later phases of station deployment. Eventually, NASA selected to halt development of the solar dynamic power generation system for space station and to reduce support for this project to two-thirds of the original level.

Impacts of Stratospheric Dynamics on Atmospheric Behavior from the Ground to Space Solar Minimum and Solar Maximum

DTIC Science & Technology

2015-12-15

from the ground to space solar minimum and solar maximum 5a. CONTRACT NUMBER BAA-76-11-01 5b. GRANT NUMBER N00173-12-1G010 5c. PROGRAM ELEMENT...atmospheric behavior from the ground to space under solar minimum and solar maximum conditions (Contract No.: N00173-12-1-G010 NRL) Project Summary...Dynamical response to solar radiative forcing is a crucial and poorly understood mechanisms. We propose to study the impacts of large dynamical events

Advance on solar instrumentation in China

NASA Astrophysics Data System (ADS)

Yan, Yihua

2015-08-01

The solar observing facilities in China are introduced with the emphasis on the development in recent years and future plans for both ground and space-based solar instrumentations. The recent solar instruments are as follows: A new generation Chinese Spectral Radioreliograph (CSRH) has been constructed at Mingantu Observing Station in Zhengxiangbaiqi, inner Mongolia of China since 2013 and is in test observations now. CSRH has two arrays with 40 × 4.5 m and 60 × 2 m parabolic antennas covering 0.4-2 GHz and 2-15 GHz frequency range. CSRH is renamed as MUSER (Mingantu Ultrawide Spectral Radiheliograph) after its accomplishment. A new 1 m vacuum solar telescope (NVST) has been installed in 2010 at Fuxian lake, 60 km away from Kunming, Yunana. At present it is the best seeing place in China. A new telescope called ONSET (Optical and NIR Solar Eruption Tracer) has been established at the same site as NVST in 2011. ONSET has been put into operation since 2013. For future ground-based plans, Chinese Giant Solar Telescope (CGST) with spatial resolution equivalent to 8m and effective area of 5m full-aperture telescope has been proposed and was formally listed into the National Plans of Major Science & Technology Infrastructures in China. The pre-study and site survey for CGST have been pursued. A 1-meter mid-infrared telescope for precise measurement of the solar magnetic field has been funded by NSFC in 2014 as a national major scientific instrument development project. This project will develop the first mid-infrared solar magnetic observation instrument in the world aiming at increasing the precision of the transverse magnetic field measurement by one order of magnitude. For future ground-based plans, we promote the Deep-space Solar Observatory (DSO) with 1-m aperture telescope to be formally funded. The ASO-S (an Advanced Space-based Solar Observatory) has been supported in background phase by Space Science Program as a small mission. Other related space solar

Auroral bright spot in Jupiter’s active region in corresponding to solar wind dynamic

NASA Astrophysics Data System (ADS)

Haewsantati, K.; Wannawichian, S.; Clarke, J. T.; Nichols, J. D.

2017-09-01

Jupiter’s polar emission has brightness whose behavior appears to be unstable. This work focuses on the bright spot in active region which is a section of Jupiter’s polar emission. Images of the aurora were taken by Advanced Camera for Surveys (ACS) onboard the Hubble Space Telescope (HST). Previously, two bright spots, which were found on 13 th May 2007, were suggested to be fixed on locations described by system III longitude. The bright spot’s origin in equatorial plane was proposed to be at distance 80-90 Jovian radii and probably associated with the solar wind properties. This study analyzes additional data on May 2007 to study long-term variation of brightness and locations of bright spots. The newly modified magnetosphere-ionosphere mapping based on VIP4 and VIPAL model is used to locate the origin of bright spot in magnetosphere. Furthermore, the Michigan Solar Wind Model or mSWiM is also used to study the variation of solar wind dynamic pressure during the time of bright spot’s observation. We found that the bright spots appear in similar locations which correspond to similar origins in magnetosphere. In addition, the solar wind dynamic pressure should probably affect the bright spot’s variation.

Solar dynamic power system definition study

NASA Technical Reports Server (NTRS)

Wallin, Wayne E.; Friefeld, Jerry M.

1988-01-01

The solar dynamic power system design and analysis study compared Brayton, alkali-metal Rankine, and free-piston Stirling cycles with silicon planar and GaAs concentrator photovoltaic power systems for application to missions beyond the Phase 2 Space Station level of technology for all power systems. Conceptual designs for Brayton and Stirling power systems were developed for 35 kWe and 7 kWe power levels. All power systems were designed for 7-year end-of-life conditions in low Earth orbit. LiF was selected for thermal energy storage for the solar dynamic systems. Results indicate that the Stirling cycle systems have the highest performance (lowest weight and area) followed by the Brayton cycle, with photovoltaic systems considerably lower in performance. For example, based on the performance assumptions used, the planar silicon power system weight was 55 to 75 percent higher than for the Stirling system. A technology program was developed to address areas wherein significant performance improvements could be realized relative to the current state-of-the-art as represented by Space Station. In addition, a preliminary evaluation of hardenability potential found that solar dynamic systems can be hardened beyond the hardness inherent in the conceptual designs of this study.

The Advanced Technology Solar Telescope: design and early construction

NASA Astrophysics Data System (ADS)

McMullin, Joseph P.; Rimmele, Thomas R.; Keil, Stephen L.; Warner, Mark; Barden, Samuel; Bulau, Scott; Craig, Simon; Goodrich, Bret; Hansen, Eric; Hegwer, Steve; Hubbard, Robert; McBride, William; Shimko, Steve; Wöger, Friedrich; Ditsler, Jennifer

2012-09-01

The National Solar Observatory’s (NSO) Advanced Technology Solar Telescope (ATST) is the first large U.S. solar telescope accessible to the worldwide solar physics community to be constructed in more than 30 years. The 4-meter diameter facility will operate over a broad wavelength range (0.35 to 28 μm ), employing adaptive optics systems to achieve diffraction limited imaging and resolve features approximately 20 km on the Sun; the key observational parameters (collecting area, spatial resolution, spectral coverage, polarization accuracy, low scattered light) enable resolution of the theoretically-predicted, fine-scale magnetic features and their dynamics which modulate the radiative output of the sun and drive the release of magnetic energy from the Sun’s atmosphere in the form of flares and coronal mass ejections. In 2010, the ATST received a significant fraction of its funding for construction. In the subsequent two years, the project has hired staff and opened an office on Maui. A number of large industrial contracts have been placed throughout the world to complete the detailed designs and begin constructing the major telescope subsystems. These contracts have included the site development, AandE designs, mirrors, polishing, optic support assemblies, telescope mount and coudé rotator structures, enclosure, thermal and mechanical systems, and high-level software and controls. In addition, design development work on the instrument suite has undergone significant progress; this has included the completion of preliminary design reviews (PDR) for all five facility instruments. Permitting required for physically starting construction on the mountaintop of Haleakalā, Maui has also progressed. This paper will review the ATST goals and specifications, describe each of the major subsystems under construction, and review the contracts and lessons learned during the contracting and early construction phases. Schedules for site construction, key factory testing of

Alternate space station freedom configuration considerations to accommodate solar dynamic power

NASA Technical Reports Server (NTRS)

Deryder, L. J.; Cruz, J. N.; Heck, M. L.; Robertson, B. P.; Troutman, P. A.

1989-01-01

The results of a technical audit of the Space Station Freedom Program conducted by the Program Director was announced in early 1989 and included a proposal to use solar dynamic power generation systems to provide primary electrical energy for orbital flight operations rather than photovoltaic solar array systems. To generate the current program baseline power of 75 kW, two or more solar concentrators approximately 50 feet in diameter would be required to replace four pairs of solar arrays whose rectangular blanket size is approximately 200 feet by 30 feet. The photovoltaic power system concept uses solar arrays to generate electricity that is stored in nickel-hydrogen batteries. The proposed concept uses the solar concentrator dishes to reflect and focus the Sun's energy to heat helium-xenon gas to drive electricity generating turbines. The purpose here is to consider the station configuration issues for incorporation of solar dynamic power system components. Key flight dynamic configuration geometry issues are addressed and an assembly sequence scenario is developed.

The advanced photovoltaic solar array program

NASA Technical Reports Server (NTRS)

Kurland, R. M.; Stella, Paul M.

1989-01-01

The background and development status of an ultralightweight flexible-blanket flatpack, fold-out solar array is presented. It is scheduled for prototype demonstration in late 1989. The Advanced Photovoltaic Solar Array (APSA) design represents a critical intermediate milestone of the goal of 300 W/kg at beginning-of-life (BOL) with specific performance characteristics of 130 W/kg (BOL) and 100 W/kg at end-of-life (EOL) for a 10-year geosynchronous geostationary earth orbit 10-kW (BOL) space power system. The APSA wing design is scalable over a power range of 2 to 15 kW and is suitable for a full range of missions including Low Earth Orbit (LEO), orbital transfer from LEO to geostationary earth orbit and interplanetary flight.

Dynamic facade module prototype development for solar radiation prevention in high rise building

NASA Astrophysics Data System (ADS)

Sega Sufia Purnama, Muhammad; Sutanto, Dalhar

2018-03-01

Solar radiation is an aspect that high rise building must avoid. The problem is, if high rise building facade can’t overcome, the solar thermal will come in the building, and its affects on the increasing of room temperature above comfort range. A type of additional facade element that could solve solar thermal in high rise building is adding a sun shading. A dynamic facade is a shade plane in high rise building that can moved or changed on outside condition such as solar movement and intensity. This research will discuss the dynamic facade module prototype development in high rise building in Jakarta. This research will be finish through some step. (1) Static shading shadow simulation. (2) Dynamic facade concept design development. (3) Dynamic shading shadow simulation. (4) Making of dynamic facade module prototype. (5) Field test for the dynamic facade module prototype. The dynamic facade in Jakarta case will be effective to solve solar transmission in high rise building rather than static facade.

Advanced solar receivers for space power

NASA Technical Reports Server (NTRS)

Strumpf, H. J.; Coombs, M. G.; Lacy, D. E.

1988-01-01

A study has been conducted to generate and evaluate advanced solar heat receiver concepts suitable for orbital application with Brayton and Stirling engine cycles in the 7-kW size range. The generated receiver designs have thermal storage capability and, when implemented, will be lighter, smaller, and/or more efficient than baseline systems such as the configuration used for the Brayton solar receiver under development by Garrett AiResearch for the NASA Space Station. In addition to the baseline designs, four other receiver concepts were designed and evaluated with respect to Brayton and Stirling engines. These concepts include a higher temperature version of the baseline receiver, a packed bed receiver, a plate-fin receiver, and a heat pipe receiver. The thermal storage for all designs is provided by the melting and freezing of a salt.

Realistic Modeling of Multi-Scale MHD Dynamics of the Solar Atmosphere

NASA Technical Reports Server (NTRS)

Kitiashvili, Irina; Mansour, Nagi N.; Wray, Alan; Couvidat, Sebastian; Yoon, Seokkwan; Kosovichev, Alexander

2014-01-01

Realistic 3D radiative MHD simulations open new perspectives for understanding the turbulent dynamics of the solar surface, its coupling to the atmosphere, and the physical mechanisms of generation and transport of non-thermal energy. Traditionally, plasma eruptions and wave phenomena in the solar atmosphere are modeled by prescribing artificial driving mechanisms using magnetic or gas pressure forces that might arise from magnetic field emergence or reconnection instabilities. In contrast, our 'ab initio' simulations provide a realistic description of solar dynamics naturally driven by solar energy flow. By simulating the upper convection zone and the solar atmosphere, we can investigate in detail the physical processes of turbulent magnetoconvection, generation and amplification of magnetic fields, excitation of MHD waves, and plasma eruptions. We present recent simulation results of the multi-scale dynamics of quiet-Sun regions, and energetic effects in the atmosphere and compare with observations. For the comparisons we calculate synthetic spectro-polarimetric data to model observational data of SDO, Hinode, and New Solar Telescope.

Recent Advances in Solar Sail Propulsion at NASA

NASA Technical Reports Server (NTRS)

Johnson, Les; Young, Roy M.; Montgomery, Edward E., IV

2006-01-01

Supporting NASA's Science Mission Directorate, the In-Space Propulsion Technology Program is developing solar sail propulsion for use in robotic science and exploration of the solar system. Solar sail propulsion will provide longer on-station operation, increased scientific payload mass fraction, and access to previously inaccessible orbits for multiple potential science missions. Two different 20-meter solar sail systems were produced and successfully completed functional vacuum testing last year in NASA Glenn's Space Power Facility at Plum Brook Station, Ohio. The sails were designed and developed by ATK Space Systems and L'Garde, respectively. These sail systems consist of a central structure with four deployable booms that support the sails. This sail designs are robust enough for deployments in a one atmosphere, one gravity environment, and are scalable to much larger solar sails-perhaps as much as 150 meters on a side. In addition, computation modeling and analytical simulations have been performed to assess the scalability of the technology to the large sizes (>150 meters) required for first generation solar sails missions. Life and space environmental effects testing of sail and component materials are also nearly complete. This paper will summarize recent technology advancements in solar sails and their successful ambient and vacuum testing.

A Model for Infusing Energy Concepts into Vocational Education Programs. Advanced Solar Systems.

ERIC Educational Resources Information Center

Delta Vocational Technical School, Marked Tree, AR.

This instructional unit consists of materials designed to help students understand terms associated with solar energy; identify components of advanced solar systems; and identify applications of solar energy in business, industry, agriculture, and photovoltaics. Included in the unit are the following materials: suggested activities, instructional…

Plasma chamber testing of advanced photovoltaic solar array coupons

NASA Technical Reports Server (NTRS)

Hillard, G. Barry

1994-01-01

The solar array module plasma interactions experiment is a space shuttle experiment designed to investigate and quantify the high voltage plasma interactions. One of the objectives of the experiment is to test the performance of the Advanced Photovoltaic Solar Array (APSA). The material properties of array blanket are also studied as electric insulators for APSA arrays in high voltage conditions. Three twelve cell prototype coupons of silicon cells were constructed and tested in a space simulation chamber.

Advanced Cloud Forecasting for Solar Energy Production

NASA Astrophysics Data System (ADS)

Werth, D. W.; Parker, M. J.

2017-12-01

A power utility must decide days in advance how it will allocate projected loads among its various generating sources. If the latter includes solar plants, the utility must predict how much energy the plants will produce - any shortfall will have to be compensated for by purchasing power as it is needed, when it is more expensive. To avoid this, utilities often err on the side of caution and assume that a relatively small amount of solar energy will be available, and allocate correspondingly more load to coal-fired plants. If solar irradiance can be predicted more accurately, utilities can be more confident that the predicted solar energy will indeed be available when needed, and assign solar plants a larger share of the future load. Solar power production is increasing in the Southeast, but is often hampered by irregular cloud fields, especially during high-pressure periods when rapid afternoon thunderstorm development can occur during what was predicted to be a clear day. We are currently developing an analog forecasting system to predict solar irradiance at the surface at the Savannah River Site in South Carolina, with the goal of improving predictions of available solar energy. Analog forecasting is based on the assumption that similar initial conditions will lead to similar outcomes, and involves the use of an algorithm to look through the weather patterns of the past to identify previous conditions (the analogs) similar to those of today. For our application, we select three predictor variables - sea-level pressure, 700mb geopotential, and 700mb humidity. These fields for the current day are compared to those from past days, and a weighted combination of the differences (defined by a cost function) is used to select the five best analog days. The observed solar irradiance values subsequent to the dates of those analogs are then combined to represent the forecast for the next day. We will explain how we apply the analog process, and compare it to existing

Pluto-Charon solar wind interaction dynamics

NASA Astrophysics Data System (ADS)

Hale, J. P. M.; Paty, C. S.

2017-05-01

This work studies Charon's effects on the Pluto-solar wind interaction using a multifluid MHD model which simulates the interactions of Pluto and Charon with the solar wind as well as with each other. Specifically, it investigates the ionospheric dynamics of a two body system in which either one or both bodies possess an ionosphere. Configurations in which Charon is directly upstream and directly downstream of Pluto are considered. Depending on ionospheric and solar wind conditions, Charon could periodically pass into the solar wind flow upstream of Pluto. The results of this study demonstrate that in these circumstances Charon modifies the upstream flow, both in the case in which Charon possesses an ionosphere, and in the case in which Charon is without an ionosphere. This modification amounts to a change in the gross structure of the interaction region when Charon possesses an ionosphere but is more localized when Charon lacks an ionosphere. Furthermore, evidence is shown that supports Charon acting to partially shield Pluto from the solar wind when it is upstream of Pluto, resulting in a decrease in ionospheric loss by Pluto.

Dynamically correlated minor bodies in the outer Solar system

NASA Astrophysics Data System (ADS)

de la Fuente Marcos, C.; de la Fuente Marcos, R.

2018-02-01

The organization of the orbits of most minor bodies in the Solar system seems to follow random patterns, the result of billions of years of chaotic dynamical evolution. Much as heterogeneous orbital behaviour is ubiquitous, dynamically coherent pairs and groups of objects are also present everywhere. Although first studied among the populations of asteroids and comets that inhabit or traverse the inner Solar system, where they are very numerous, at least one asteroid family has been confirmed to exist in the outer Solar system and two other candidates have been proposed in the literature. Here, we perform a systematic search for statistically significant pairs and groups of dynamically correlated objects through those with semimajor axis greater than 25 au, applying a novel technique that uses the angular separations of orbital poles and perihelia together with the differences in time of perihelion passage to single out pairs of relevant objects. Our analysis recovers well-known, dynamically coherent pairs and groups of comets and trans-Neptunian objects and uncovers a number of new ones, prime candidates for further spectroscopic study.

Advanced Solar Observatory (ASO) accommodations requirements study

NASA Technical Reports Server (NTRS)

1989-01-01

Results of an accommodations analysis for the Advanced Solar Observatory on Space Station Freedom are reported. Concepts for the High Resolution Telescope Cluster, Pinhole/Occulter Facility, and High Energy Cluster were developed which can be accommodated on Space Station Freedom. It is shown that workable accommodations concepts are possible. Areas of emphasis for the next stage of engineering development are identified.

The Helioseismic and Magnetic Imager (HMI) Investigation for the Solar Dynamics Observatory (SDO)

NASA Technical Reports Server (NTRS)

Scherrer, Philip Hanby; Schou, Jesper; Bush, R. I.; Kosovichev, A. G.; Bogart, R. S.; Hoeksema, J. T.; Liu, Y.; Duvall, T. L., Jr.; Zhao, J.; Title, A. M.;

Distributed solar radiation fast dynamic measurement for PV cells

NASA Astrophysics Data System (ADS)

Wan, Xuefen; Yang, Yi; Cui, Jian; Du, Xingjing; Zheng, Tao; Sardar, Muhammad Sohail

2017-10-01

To study the operating characteristics about PV cells, attention must be given to the dynamic behavior of the solar radiation. The dynamic behaviors of annual, monthly, daily and hourly averages of solar radiation have been studied in detail. But faster dynamic behaviors of solar radiation need more researches. The solar radiation random fluctuations in minute-long or second-long range, which lead to alternating radiation and cool down/warm up PV cell frequently, decrease conversion efficiency. Fast dynamic processes of solar radiation are mainly relevant to stochastic moving of clouds. Even in clear sky condition, the solar irradiations show a certain degree of fast variation. To evaluate operating characteristics of PV cells under fast dynamic irradiation, a solar radiation measuring array (SRMA) based on large active area photodiode, LoRa spread spectrum communication and nanoWatt MCU is proposed. This cross photodiodes structure tracks fast stochastic moving of clouds. To compensate response time of pyranometer and reduce system cost, the terminal nodes with low-cost fast-responded large active area photodiode are placed besides positions of tested PV cells. A central node, consists with pyranometer, large active area photodiode, wind detector and host computer, is placed in the center of the central topologies coordinate to scale temporal envelope of solar irradiation and get calibration information between pyranometer and large active area photodiodes. In our SRMA system, the terminal nodes are designed based on Microchip's nanoWatt XLP PIC16F1947. FDS-100 is adopted for large active area photodiode in terminal nodes and host computer. The output current and voltage of each PV cell are monitored by I/V measurement. AS62-T27/SX1278 LoRa communication modules are used for communicating between terminal nodes and host computer. Because the LoRa LPWAN (Low Power Wide Area Network) specification provides seamless interoperability among Smart Things without the

The NASA Space Solar Cell Advanced Research Program

NASA Technical Reports Server (NTRS)

Flood, Dennis J.

1989-01-01

Two major requirements for space solar cells are high efficiency and survivability in the naturally occurring charged particle space radiation environment. Performance limits for silicon space cells are well understood. Advanced cells using GaAs and InP are under development to provide significantly improved capability for the future.

Ultrafast Electron Dynamics in Solar Energy Conversion.

PubMed

Ponseca, Carlito S; Chábera, Pavel; Uhlig, Jens; Persson, Petter; Sundström, Villy

2017-08-23

Electrons are the workhorses of solar energy conversion. Conversion of the energy of light to electricity in photovoltaics, or to energy-rich molecules (solar fuel) through photocatalytic processes, invariably starts with photoinduced generation of energy-rich electrons. The harvesting of these electrons in practical devices rests on a series of electron transfer processes whose dynamics and efficiencies determine the function of materials and devices. To capture the energy of a photogenerated electron-hole pair in a solar cell material, charges of opposite sign have to be separated against electrostatic attractions, prevented from recombining and being transported through the active material to electrodes where they can be extracted. In photocatalytic solar fuel production, these electron processes are coupled to chemical reactions leading to storage of the energy of light in chemical bonds. With the focus on the ultrafast time scale, we here discuss the light-induced electron processes underlying the function of several molecular and hybrid materials currently under development for solar energy applications in dye or quantum dot-sensitized solar cells, polymer-fullerene polymer solar cells, organometal halide perovskite solar cells, and finally some photocatalytic systems.

Solar Prominence Fine Structure and Dynamics

NASA Astrophysics Data System (ADS)

Berger, Thomas

2014-01-01

We review recent observational and theoretical results on the fine structure and dynamics of solar prominences, beginning with an overview of prominence classifications, the proposal of possible new ``funnel prominence'' classification, and a discussion of the recent ``solar tornado'' findings. We then focus on quiescent prominences to review formation, down-flow dynamics, and the ``prominence bubble'' phenomena. We show new observations of the prominence bubble Rayleigh-Taylor instability triggered by a Kelvin-Helmholtz shear flow instability occurring along the bubble boundary. Finally we review recent studies on plasma composition of bubbles, emphasizing that differential emission measure (DEM) analysis offers a more quantitative analysis than photometric comparisons. In conclusion, we discuss the relation of prominences to coronal magnetic flux ropes, proposing that prominences can be understood as partially ionized condensations of plasma forming the return flow of a general magneto-thermal convection in the corona.

Deployment dynamics and control of large-scale flexible solar array system with deployable mast

NASA Astrophysics Data System (ADS)

Li, Hai-Quan; Liu, Xiao-Feng; Guo, Shao-Jing; Cai, Guo-Ping

2016-10-01

In this paper, deployment dynamics and control of large-scale flexible solar array system with deployable mast are investigated. The adopted solar array system is introduced firstly, including system configuration, deployable mast and solar arrays with several mechanisms. Then dynamic equation of the solar array system is established by the Jourdain velocity variation principle and a method for dynamics with topology changes is introduced. In addition, a PD controller with disturbance estimation is designed to eliminate the drift of spacecraft mainbody. Finally the validity of the dynamic model is verified through a comparison with ADAMS software and the deployment process and dynamic behavior of the system are studied in detail. Simulation results indicate that the proposed model is effective to describe the deployment dynamics of the large-scale flexible solar arrays and the proposed controller is practical to eliminate the drift of spacecraft mainbody.

Dynamic electrical response of solar cells

NASA Technical Reports Server (NTRS)

Catani, J. P.

1981-01-01

The dynamic response of a solar generator is of primary importance as much for the design and development of electrical power conditioning hardware as for the analysis of electromagnetic compatibility. A mathematical model of photo-batteries was developed on the basis of impedance measurements performed under differing conditions of temperature, light intensity, before and after irradiation. This model was compared with that derived from PN junction theory and to static measurements. These dynamic measurements enabled the refinement of an integration method capable of determining, under normal laboratory conditions, the dynamic response of a generator to operational lighting conditions.

2-kW Solar Dynamic Space Power System Tested in Lewis' Thermal Vacuum Facility

NASA Technical Reports Server (NTRS)

1995-01-01

Working together, a NASA/industry team successfully operated and tested a complete solar dynamic space power system in a large thermal vacuum facility with a simulated sun. This NASA Lewis Research Center facility, known as Tank 6 in building 301, accurately simulates the temperatures, high vacuum, and solar flux encountered in low-Earth orbit. The solar dynamic space power system shown in the photo in the Lewis facility, includes the solar concentrator and the solar receiver with thermal energy storage integrated with the power conversion unit. Initial testing in December 1994 resulted in the world's first operation of an integrated solar dynamic system in a relevant environment.

The Solar Dynamics Observatory

NASA Technical Reports Server (NTRS)

Pesnell, William D.

2008-01-01

The Solar Dynamics Observatory (SDO) is the first Space Weather Mission in NASA's Living With a Star Program. SDO's main goal is to understand, driving towards a predictive capability, those solar variations that influence life on Earth and humanity's technological systems. The past decade has seen an increasing emphasis on understanding the entire Sun, from the nuclear reactions at the core to the development and loss of magnetic loops in the corona. SDO's three science investigations (HMI, AIA, and EVE) will determine how the Sun's magnetic field is generated and structured, how this stored magnetic energy is released into the heliosphere and geospace as the solar wind, energetic particles, and variations in the solar irradiance. SDO will return full-disk Dopplergrams, full-disk vector magnetograms, full-disk images at nine EIUV wavelengths, and EUV spectral irradiances, all taken at a rapid cadence. This means you can 'observe the database' to study events, but we can also move forward in producing quantitative models of what the Sun is doing today. SDO is scheduled to launch in 2008 on an Atlas V rocket from the Kennedy Space Center, Cape Canaveral, Florida. The satellite will fly in a 28 degree inclined geosynchronous orbit about the longitude of New Mexico, where a dedicated Ka-band ground station will receive the 150 Mbps data flow. How SDO data will transform the study of the Sun and its affect on Space Weather studies will be discussed.

Daniel K. Inouye Solar Telescope: High-resolution observing of the dynamic Sun

NASA Astrophysics Data System (ADS)

Tritschler, A.; Rimmele, T. R.; Berukoff, S.; Casini, R.; Kuhn, J. R.; Lin, H.; Rast, M. P.; McMullin, J. P.; Schmidt, W.; Wöger, F.; DKIST Team

2016-11-01

The 4-m aperture Daniel K. Inouye Solar Telescope (DKIST) formerly known as the Advanced Technology Solar Telescope (ATST) is currently under construction on Haleakalā (Maui, Hawai'i) projected to start operations in 2019. At the time of completion, DKIST will be the largest ground-based solar telescope providing unprecedented resolution and photon collecting power. The DKIST will be equipped with a set of first-light facility-class instruments offering unique imaging, spectroscopic and spectropolarimetric observing opportunities covering the visible to infrared wavelength range. This first-light instrumentation suite will include: a Visible Broadband Imager (VBI) for high-spatial and -temporal resolution imaging of the solar atmosphere; a Visible Spectro-Polarimeter (ViSP) for sensitive and accurate multi-line spectropolarimetry; a Fabry-Pérot based Visible Tunable Filter (VTF) for high-spatial resolution spectropolarimetry; a fiber-fed Diffraction-Limited Near Infra-Red Spectro-Polarimeter (DL-NIRSP) for two-dimensional high-spatial resolution spectropolarimetry (simultaneous spatial and spectral information); and a Cryogenic Near Infra-Red Spectro-Polarimeter (Cryo-NIRSP) for coronal magnetic field measurements and on-disk observations of, e.g., the CO lines at 4.7 μm. We will provide an overview of the DKIST's unique capabilities with strong focus on the first-light instrumentation suite, highlight some of the additional properties supporting observations of transient and dynamic solar phenomena, and touch on some operational strategies and the DKIST critical science plan.

No Photon Left Behind: Advanced Optics at ARPA-E for Buildings and Solar Energy

NASA Astrophysics Data System (ADS)

Branz, Howard M.

2015-04-01

Key technology challenges in building efficiency and solar energy utilization require transformational optics, plasmonics and photonics technologies. We describe advanced optical technologies funded by the Advanced Research Projects Agency - Energy. Buildings technologies include a passive daytime photonic cooler, infra-red computer vision mapping for energy audit, and dual-band electrochromic windows based on plasmonic absorption. Solar technologies include novel hybrid energy converters that combine high-efficiency photovoltaics with concentrating solar thermal collection and storage. Because the marginal cost of thermal energy storage is low, these systems enable generation of inexpensive and dispatchable solar energy that can be deployed when the sun doesn't shine. The solar technologies under development include nanoparticle plasmonic spectrum splitting, Rugate filter interference structures and photovoltaic cells that can operate efficiently at over 400° C.

NASA's Solar Dynamics Observatory Unveils New Images

NASA Image and Video Library

2017-12-08

Scientists presented the first images from NASA's Solar Dynamics Observatory [SDO] during a special "first light" press conference, Wednesday, April 21 2010, at held at the Newseum in Washington DC. Credit: NASA/GSFC

Solar Dynamics Observatory (SDO) HGAS Induced Jitter

NASA Technical Reports Server (NTRS)

Liu, Alice; Blaurock, Carl; Liu, Kuo-Chia; Mule, Peter

2008-01-01

This paper presents the results of a comprehensive assessment of High Gain Antenna System induced jitter on the Solar Dynamics Observatory. The jitter prediction is created using a coupled model of the structural dynamics, optical response, control systems, and stepper motor actuator electromechanical dynamics. The paper gives an overview of the model components, presents the verification processes used to evaluate the models, describes validation and calibration tests and model-to-measurement comparison results, and presents the jitter analysis methodology and results.

Solar Flare Dynamic Microwave Imaging with EOVSA

NASA Astrophysics Data System (ADS)

Gary, D. E.; Chen, B.; Nita, G. M.; Fleishman, G. D.; Yu, S.; White, S. M.; Hurford, G. J.; McTiernan, J. M.

2017-12-01

The Expanded Owens Valley Solar Array (EOVSA) is both an expansion of our existing solar array and serves as a prototype for a much larger future project, the Frequency Agile Solar Radiotelescope (FASR). EOVSA is now complete, and is producing daily imaging of the full solar disk, including active regions and solar radio bursts at hundreds of frequencies in the range 2.8-18 GHz. We present highlights of the 1-s-cadence dynamic imaging spectroscropy of radio bursts we have obtained to date, along with deeper analysis of multi-wavelength observations and modeling of a well-observed burst. These observations are revealing the full life-cycle of the trapped population of high-energy electrons, from their initial acceleration and subsequent energy-evolution to their eventual decay through escape and thermalization. All of our data are being made available for download in both quick-look image form and in the form of the community-standard CASA measurement sets for subsequent imaging and analysis.

Electric power - Photovoltaic or solar dynamic?

NASA Technical Reports Server (NTRS)

Thomas, R. L.; Hallinan, G. J.; Hieatt, J. L.

1985-01-01

The design of the power system for supplying the Space Station with insolation-generated electricity is the main Phase B task at NASA-Lewis Center. The advantages and limitations of two types of power systems, the photovoltaic arrays (PV) and the solar dynamic system (SD), are discussed from the points of view of cost, overall systems integration, and growth. Subsystems of each of these options are described, and a sketch of a projected SD system is shown. The PV technology is well developed and proven, but its low efficiency calls for solar arrays of large areas, which affect station dynamics, control, and drag compensation. The SD systems would be less costly to operate than VP, and are more efficient, needing less deployed area. The major drawback of the SD is its infancy. The conservative and forgiving designs for some of its components must still be created and tested, and the development risks assessed.

Testing relativity with solar system dynamics

NASA Technical Reports Server (NTRS)

Hellings, R. W.

1984-01-01

A major breakthrough is described in the accuracy of Solar System dynamical tests of relativistic gravity. The breakthrough was achieved by factoring in ranging data from Viking Landers 1 and 2 from the surface of Mars. Other key data sources included optical transit circle observations, lunar laser ranging, planetary radar, and spacecraft (Mariner 9 to Mars and Mariner 10 to Mercury). The Solar System model which is used to fit the data and the process by which such fits are performed are explained and results are discussed. The results are fully consistent with the predictions of General Relativity.

Phase change energy storage for solar dynamic power systems

NASA Technical Reports Server (NTRS)

Chiaramonte, F. P.; Taylor, J. D.

1992-01-01

This paper presents the results of a transient computer simulation that was developed to study phase change energy storage techniques for Space Station Freedom (SSF) solar dynamic (SD) power systems. Such SD systems may be used in future growth SSF configurations. Two solar dynamic options are considered in this paper: Brayton and Rankine. Model elements consist of a single node receiver and concentrator, and takes into account overall heat engine efficiency and power distribution characteristics. The simulation not only computes the energy stored in the receiver phase change material (PCM), but also the amount of the PCM required for various combinations of load demands and power system mission constraints. For a solar dynamic power system in low earth orbit, the amount of stored PCM energy is calculated by balancing the solar energy input and the energy consumed by the loads corrected by an overall system efficiency. The model assumes an average 75 kW SD power system load profile which is connected to user loads via dedicated power distribution channels. The model then calculates the stored energy in the receiver and subsequently estimates the quantity of PCM necessary to meet peaking and contingency requirements. The model can also be used to conduct trade studies on the performance of SD power systems using different storage materials.

Phase change energy storage for solar dynamic power systems

NASA Astrophysics Data System (ADS)

Chiaramonte, F. P.; Taylor, J. D.

This paper presents the results of a transient computer simulation that was developed to study phase change energy storage techniques for Space Station Freedom (SSF) solar dynamic (SD) power systems. Such SD systems may be used in future growth SSF configurations. Two solar dynamic options are considered in this paper: Brayton and Rankine. Model elements consist of a single node receiver and concentrator, and takes into account overall heat engine efficiency and power distribution characteristics. The simulation not only computes the energy stored in the receiver phase change material (PCM), but also the amount of the PCM required for various combinations of load demands and power system mission constraints. For a solar dynamic power system in low earth orbit, the amount of stored PCM energy is calculated by balancing the solar energy input and the energy consumed by the loads corrected by an overall system efficiency. The model assumes an average 75 kW SD power system load profile which is connected to user loads via dedicated power distribution channels. The model then calculates the stored energy in the receiver and subsequently estimates the quantity of PCM necessary to meet peaking and contingency requirements. The model can also be used to conduct trade studies on the performance of SD power systems using different storage materials.

NREL's Education Program in Action in the Concentrating Solar Power Program Advanced Materials Task

NASA Astrophysics Data System (ADS)

Kennedy, Cheryl

2010-03-01

Concentrating solar power (CSP) technologies use large mirrors to concentrate sunlight and the thermal energy collected is converted to electricity. The CSP industry is growing rapidly and is expected to reach 25 GW globally by 2020. Cost target goals are for CSP technologies to produce electricity competitive with intermediate-load power generation (i.e., natural gas) by 2015 with 6 hours of thermal storage and competitive in carbon constrained base load power markets (i.e., coal) by 2020 with 12-17 hours of thermal storage. The solar field contributes more than 40% of the total cost of a parabolic trough plant and together the mirrors and receivers contribute more than 25% of the installed solar field cost. CSP systems cannot hit these targets without aggressive cost reductions and revolutionary performance improvements from technology advances. NREL's Advanced Materials task in the CSP Advanced R&D project performs research to develop low cost, high performance, durable solar reflector and high-temperature receiver materials to meet these needs. The Advanced Materials task leads the world in this research and the task's reliance on NREL's educational program will be discussed.

The Advanced Technology Solar Telescope mount assembly

NASA Astrophysics Data System (ADS)

Warner, Mark; Cho, Myung; Goodrich, Bret; Hansen, Eric; Hubbard, Rob; Lee, Joon Pyo; Wagner, Jeremy

2006-06-01

When constructed on the summit of Haleakala on the island of Maui, Hawaii, the Advanced Technology Solar Telescope (ATST) will be the world's largest solar telescope. The ATST is a unique design that utilizes a state-of-the-art off-axis Gregorian optical layout with five reflecting mirrors delivering light to a Nasmyth instrument rotator, and nine reflecting mirrors delivering light to an instrument suite located on a large diameter rotating coude lab. The design of the telescope mount structure, which supports and positions the mirrors and scientific instruments, has presented noteworthy challenges to the ATST engineering staff. Several novel design solutions, as well as adaptations of existing telescope technologies to the ATST application, are presented in this paper. Also shown are plans for the control system and drives of the structure.

Heat receivers for solar dynamic space power systems

NASA Astrophysics Data System (ADS)

Perez-Davis, Marla Esther

A review of state-of-the-art technology is presented and discussed for phase change materials. Some of the advanced solar dynamic designs developed as part of the Advanced Heat Receiver Conceptual Design Study performed for LeRC are discussed. The heat receivers are analyzed and several recommendations are proposed, including two new concepts. The first concept evaluated the effect of tube geometries inside the heat receiver. It was found that a triangular configuration would provide better heat transfer to the working fluid, although not necessarily with a reduction in receiver size. A sensible heat receiver considered in this study uses vapor grown graphite fiber-carbon (VGCF/C) composite as the thermal storage media and was designed for a 7 kW Brayton engine. The proposed heat receiver stores the required energy to power the system during eclipse in the VGCF/C composite. The heat receiver analysis was conducted through the Systems Improved Numerical Differencing Analyzer and Fluid Integrator (SINDA) software package. The proposed heat receiver compares well with other latent and advanced sensible heat receivers while avoiding the problems associated with latent heat storage salts and liquid metal heat pipes. The weight and size of the system can be optimized by changes in geometry and technology advances for this new material. In addition to the new concepts, the effect of atomic oxygen on several materials is reviewed. A test was conducted for atomic oxygen attack on boron nitride, which experienced a negligible mass loss when exposed to an atomic oxygen fluence of 5 x 10 exp 21 atoms/sq cm. This material could be used to substitute the graphite aperture plate of the heat receiver.

NASA Provides Coast-to-Coast Coverage of Aug. 21 Solar Eclipse (Solar Dynamics Observatory)

NASA Image and Video Library

2017-08-21

On Monday, Aug. 21, NASA provided coast-to-coast coverage of the solar eclipse across America – featuring views of the phenomenon from unique vantage points, including from the ground, from aircraft, and from spacecraft including the ISS, during a live broadcast seen on NASA Television and the agency’s website. This is footage from NASA’s Solar Dynamics Observatory.

Solar Sail Loads, Dynamics, and Membrane Studies

NASA Technical Reports Server (NTRS)

Slade, K. N.; Belvin, W. K.; Behun, V.

2002-01-01

While a number of solar sail missions have been proposed recently, these missions have not been selected for flight validation. Although the reasons for non-selection are varied, principal among them is the lack of subsystem integration and ground testing. This paper presents some early results from a large-scale ground testing program for integrated solar sail systems. In this series of tests, a 10 meter solar sail tested is subjected to dynamic excitation both in ambient atmospheric and vacuum conditions. Laser vibrometry is used to determine resonant frequencies and deformation shapes. The results include some low-order sail modes which only can be seen in vacuum, pointing to the necessity of testing in that environment.

Vortex, ULF wave and Aurora Observation after Solar Wind Dynamic Pressure Change

NASA Astrophysics Data System (ADS)

Shi, Q.

2017-12-01

Here we will summarize our recent study and show some new results on the Magnetosphere and Ionosphere Response to Dynamic Pressure Change/disturbances in the Solar Wind and foreshock regions. We study the step function type solar wind dynamic pressure change (increase/decrease) interaction with the magnetosphere using THEMIS satellites at both dayside and nightside in different geocentric distances. Vortices generated by the dynamic pressure change passing along the magnetopause are found and compared with model predictions. ULF waves and vortices are excited in the dayside and nightside plasma sheet when dynamic pressure change hit the magnetotail. The related ionospheric responses, such as aurora and TCVs, are also investigated. We compare Global MHD simulations with the observations. We will also show some new results that dayside magnetospheric FLRs might be caused by foreshock structures.Shi, Q. Q. et al. (2013), THEMIS observations of ULF wave excitation in the nightside plasma sheet during sudden impulse events, J. Geophys. Res. Space Physics, 118, doi:10.1029/2012JA017984. Shi, Q. Q. et al. (2014), Solar wind pressure pulse-driven magnetospheric vortices and their global consequences, J. Geophys. Res. Space Physics, 119, doi:10.1002/2013JA019551. Tian, A.M. et al.(2016), Dayside magnetospheric and ionospheric responses to solar wind pressure increase: Multispacecraft and ground observations, J. Geophys. Res., 121, doi:10.1002/2016JA022459. Shen, X.C. et al.(2015), Magnetospheric ULF waves with increasing amplitude related to solar wind dynamic pressure changes: THEMIS observations, J. Geophys. Res., 120, doi:10.1002/2014JA020913Zhao, H. Y. et al. (2016), Magnetospheric vortices and their global effect after a solar wind dynamic pressure decrease, J. Geophys. Res. Space Physics, 121, doi:10.1002/2015JA021646. Shen, X. C., et al. (2017), Dayside magnetospheric ULF wave frequency modulated by a solar wind dynamic pressure negative impulse, J. Geophys. Res

Advanced solar box and flat plate collector cookers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grupp, M.; Bergler, H.

Several new solar cooker systems have been developed at Synopsis during the last years: advanced box type cookers, featuring an optimized heat transfer from the absorber into the cooking vessel; flat plate cookers, based on a particular two-way collector with air as transfer fluid; flat plate cookers with heat-pipe transfer; specialized cookers for the baking of bread and flat bread. The working principle of these cookers is described, the structure of a thermal simulation model and results of thermal tests are presented. The results of the first year of local production and use of advanced boxes in India are reported.

NASA's Solar Dynamics Observatory (SDO): A Systems Approach to a Complex Mission

NASA Technical Reports Server (NTRS)

Ruffa, John A.; Ward, David K.; Bartusek, LIsa M.; Bay, Michael; Gonzales, Peter J.; Pesnell, William D.

2012-01-01

The Solar Dynamics Observatory (SDO) includes three advanced instruments, massive science data volume, stringent science data completeness requirements, and a custom ground station to meet mission demands. The strict instrument science requirements imposed a number of challenging drivers on the overall mission system design, leading the SDO team to adopt an integrated systems engineering presence across all aspects of the mission to ensure that mission science requirements would be met. Key strategies were devised to address these system level drivers and mitigate identified threats to mission success. The global systems engineering team approach ensured that key drivers and risk areas were rigorously addressed through all phases of the mission, leading to the successful SDO launch and on-orbit operation. Since launch, SDO's on-orbit performance has met all mission science requirements and enabled groundbreaking science observations, expanding our understanding of the Sun and its dynamic processes.

NASA's Solar Dynamics Observatory (SDO): A Systems Approach to a Complex Mission

NASA Technical Reports Server (NTRS)

Ruffa, John A.; Ward, David K.; Bartusek, Lisa M.; Bay, Michael; Gonzales, Peter J.; Pesnell, William D.

2012-01-01

The Solar Dynamics Observatory (SDO) includes three advanced instruments, massive science data volume, stringent science data completeness requirements, and a custom ground station to meet mission demands. The strict instrument science requirements imposed a number of challenging drivers on the overall mission system design, leading the SDO team to adopt an integrated systems engineering presence across all aspects of the mission to ensure that mission science requirements would be met. Key strategies were devised to address these system level drivers and mitigate identified threats to mission success. The global systems engineering team approach ensured that key drivers and risk areas were rigorously addressed through all phases of the mission, leading to the successful SDO launch and on-orbit operation. Since launch, SDO s on-orbit performance has met all mission science requirements and enabled groundbreaking science observations, expanding our understanding of the Sun and its dynamic processes.

Recent advances in plasmonic dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Rho, Won-Yeop; Song, Da Hyun; Yang, Hwa-Young; Kim, Ho-Sub; Son, Byung Sung; Suh, Jung Sang; Jun, Bong-Hyun

2018-02-01

Dye-sensitized solar cells (DSSCs) are among the best devices in generating electrons from solar light energy due to their high efficiency, low-cost in processing and transparency in building integrated photovoltaics. There are several ways to improve their energy-conversion efficiency, such as increasing light harvesting and electron transport, of which plasmon and 3-dimensional nanostructures are greatly capable. We review recent advances in plasmonic effects which depend on optimizing sizes, shapes, alloy compositions and integration of metal nanoparticles. Different methods to integrate metal nanoparticles into 3-dimensional nanostructures are also discussed. This review presents a guideline for enhancing the energy-conversion efficiency of DSSCs by utilizing metal nanoparticles that are incorporated into 3-dimensional nanostructures.

Mid-level Solar Flare

NASA Image and Video Library

2014-10-02

NASA's Solar Dynamics Observatory captured these images of a solar flare on Oct. 2, 2014. The solar flare is the bright flash of light on the right limb of the sun. A burst of solar material erupting out into space can be seen just below it. Read more: 1.usa.gov/1mW8rel Credit: NASA/Goddard/SDO NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Quantum-Dot-Based Solar Cells: Recent Advances, Strategies, and Challenges.

PubMed

Kim, Mee Rahn; Ma, Dongling

2015-01-02

Among next-generation photovoltaic systems requiring low cost and high efficiency, quantum dot (QD)-based solar cells stand out as a very promising candidate because of the unique and versatile characteristics of QDs. The past decade has already seen rapid conceptual and technological advances on various aspects of QD solar cells, and diverse opportunities, which QDs can offer, predict that there is still ample room for further development and breakthroughs. In this Perspective, we first review the attractive advantages of QDs, such as size-tunable band gaps and multiple exciton generation (MEG), beneficial to solar cell applications. We then analyze major strategies, which have been extensively explored and have largely contributed to the most recent and significant achievements in QD solar cells. Finally, their high potential and challenges are discussed. In particular, QD solar cells are considered to hold immense potential to overcome the theoretical efficiency limit of 31% for single-junction cells.

Advances in thin-film solar cells for lightweight space photovoltaic power

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.; Bailey, Sheila G.; Flood, Dennis J.

1989-01-01

The present stature and current research directions of photovoltaic arrays as primary power systems for space are reviewed. There have recently been great advances in the technology of thin-film solar cells for terrestrial applications. In a thin-film solar cell the thickness of the active element is only a few microns; transfer of this technology to space arrays could result in ultralow-weight solar arrays with potentially large gains in specific power. Recent advances in thin-film solar cells are reviewed, including polycrystalline copper-indium selenide (CuInSe2) and related I-III-VI2 compounds, polycrystalline cadmium telluride and related II-VI compounds, and amorphous silicon:hydrogen and alloys. The best experimental efficiency on thin-film solar cells to date is 12 percent AMO for CuIn Se2. This efficiency is likely to be increased in the next few years. The radiation tolerance of thin-film materials is far greater than that of single-crystal materials. CuIn Se2 shows no degradation when exposed to 1 MeV electrons. Experimental evidence also suggests that most of all of the radiation damage on thin-films can be removed by a low temperature anneal. The possibility of thin-film multibandgap cascade solar cells is discussed, including the tradeoffs between monolithic and mechanically stacked cells. The best current efficiency for a cascade is 12.5 percent AMO for an amorphous silicon on CuInSe2 multibandgap combination. Higher efficiencies are expected in the future. For several missions, including solar-electric propulsion, a manned Mars mission, and lunar exploration and manufacturing, thin-film photovolatic arrays may be a mission-enabling technology.

Mid-level Solar Flare

NASA Image and Video Library

2017-12-08

SDO View of M7.3 Class Solar Flare on Oct. 2, 2014 NASA's Solar Dynamics Observatory captured this image of an M7.3 class solar flare on Oct. 2, 2014. The solar flare is the bright flash of light on the right limb of the sun. A burst of solar material erupting out into space can be seen just below it. Credit: NASA/Goddard/SDO NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

NASA's Solar Dynamics Observatory Unveils New Images

NASA Image and Video Library

2010-04-20

Dean Pesnell, SDO project scientist, Goddard Space Flight Center in Greenbelt, Md. speaks during a briefing to discuss recent images from NASA's Solar Dynamics Observatory, or SDO, Wednesday, April 21, 2010, at the Newseum in Washington. Photo Credit: (NASA/Carla Cioffi)

Solar wind dynamic pressure and electric field as the main factors controlling Saturn's aurorae.

PubMed

Crary, F J; Clarke, J T; Dougherty, M K; Hanlon, P G; Hansen, K C; Steinberg, J T; Barraclough, B L; Coates, A J; Gérard, J-C; Grodent, D; Kurth, W S; Mitchell, D G; Rymer, A M; Young, D T

2005-02-17

The interaction of the solar wind with Earth's magnetosphere gives rise to the bright polar aurorae and to geomagnetic storms, but the relation between the solar wind and the dynamics of the outer planets' magnetospheres is poorly understood. Jupiter's magnetospheric dynamics and aurorae are dominated by processes internal to the jovian system, whereas Saturn's magnetosphere has generally been considered to have both internal and solar-wind-driven processes. This hypothesis, however, is tentative because of limited simultaneous solar wind and magnetospheric measurements. Here we report solar wind measurements, immediately upstream of Saturn, over a one-month period. When combined with simultaneous ultraviolet imaging we find that, unlike Jupiter, Saturn's aurorae respond strongly to solar wind conditions. But in contrast to Earth, the main controlling factor appears to be solar wind dynamic pressure and electric field, with the orientation of the interplanetary magnetic field playing a much more limited role. Saturn's magnetosphere is, therefore, strongly driven by the solar wind, but the solar wind conditions that drive it differ from those that drive the Earth's magnetosphere.

Analysis of shadowing effects on MIR photovoltaic and solar dynamic power systems

NASA Technical Reports Server (NTRS)

Fincannon, James

1995-01-01

The NASA Lewis Research Center is currently working with RSC-Energia, the Russian Space Agency, and Allied Signal in developing a flight demonstration solar dynamic power system. This type of power system is dependent upon solar flux that is reflected and concentrated into a thermal storage system to provide the thermal energy input to a closed-cycle Brayton heat engine. The solar dynamic unit will be flown on the Russian Mir space station in anticipation of use on the International Space Station Alpha. By the time the power system is launched, the Mir will be a spatially complex configuration which will have, in addition to the three-gimbaled solar dynamic unit, eleven solar array wings that are either fixed or track the Sun along one axis and a variety or repositionable habitation and experiment modules. The proximity of arrays to modules creates a situation which makes it highly probable that there will be varying solar flux due to shadowing on the solar dynamic unit and some of the arrays throughout the orbit. Shadowing causes fluctuations in the power output from the arrays and the solar dynamic power system, thus reducing the energy capabilities of the spacecraft. An assessment of the capabilities of the power system under these conditions is an important part in influencing the design and operations of the spacecraft and predicting its energy performance. This paper describes the results obtained from using the Orbiting Spacecraft Shadowing Analysis Station program that was integrated into the Station Power Analysis for Capability Evaluation (SPACE) electrical power system computer program. OSSA allows one to consider the numerous complex factors for analyzing the shadowing effects on the electrical power system including the variety of spacecraft hardware geometric configurations, yearly and daily orbital variations in the vehicle attitude and orbital maneuvers (for communications coverage, payload pointing requirements and rendezvous/docking with other

Analysis of shadowing effects on MIR photovoltaic and solar dynamic power systems

NASA Astrophysics Data System (ADS)

Fincannon, James

1995-05-01

The NASA Lewis Research Center is currently working with RSC-Energia, the Russian Space Agency, and Allied Signal in developing a flight demonstration solar dynamic power system. This type of power system is dependent upon solar flux that is reflected and concentrated into a thermal storage system to provide the thermal energy input to a closed-cycle Brayton heat engine. The solar dynamic unit will be flown on the Russian Mir space station in anticipation of use on the International Space Station Alpha. By the time the power system is launched, the Mir will be a spatially complex configuration which will have, in addition to the three-gimbaled solar dynamic unit, eleven solar array wings that are either fixed or track the Sun along one axis and a variety or repositionable habitation and experiment modules. The proximity of arrays to modules creates a situation which makes it highly probable that there will be varying solar flux due to shadowing on the solar dynamic unit and some of the arrays throughout the orbit. Shadowing causes fluctuations in the power output from the arrays and the solar dynamic power system, thus reducing the energy capabilities of the spacecraft. An assessment of the capabilities of the power system under these conditions is an important part in influencing the design and operations of the spacecraft and predicting its energy performance. This paper describes the results obtained from using the Orbiting Spacecraft Shadowing Analysis Station program that was integrated into the Station Power Analysis for Capability Evaluation (SPACE) electrical power system computer program. OSSA allows one to consider the numerous complex factors for analyzing the shadowing effects on the electrical power system including the variety of spacecraft hardware geometric configurations, yearly and daily orbital variations in the vehicle attitude and orbital maneuvers (for communications coverage, payload pointing requirements and rendezvous/docking with other

Solar Thermoelectricity via Advanced Latent Heat Storage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Olsen, Michele L.; Rea, J.; Glatzmaier, Greg C.

2016-05-31

We report on a new modular, dispatchable, and cost-effective solar electricity-generating technology. Solar ThermoElectricity via Advanced Latent heat Storage (STEALS) integrates several state-of-the-art technologies to provide electricity on demand. In the envisioned STEALS system, concentrated sunlight is converted to heat at a solar absorber. The heat is then delivered to either a thermoelectric (TE) module for direct electricity generation, or to charge a phase change material for thermal energy storage, enabling subsequent generation during off-sun hours, or both for simultaneous electricity production and energy storage. The key to making STEALS a dispatchable technology lies in the development of a 'thermalmore » valve,' which controls when heat is allowed to flow through the TE module, thus controlling when electricity is generated. The current project addresses each of the three major subcomponents, (i) the TE module, (ii) the thermal energy storage system, and (iii) the thermal valve. The project also includes system-level and techno- economic modeling of the envisioned integrated system and will culminate in the demonstration of a laboratory-scale STEALS prototype capable of generating 3kWe.« less

Solar thermoelectricity via advanced latent heat storage

NASA Astrophysics Data System (ADS)

Olsen, M. L.; Rea, J.; Glatzmaier, G. C.; Hardin, C.; Oshman, C.; Vaughn, J.; Roark, T.; Raade, J. W.; Bradshaw, R. W.; Sharp, J.; Avery, A. D.; Bobela, D.; Bonner, R.; Weigand, R.; Campo, D.; Parilla, P. A.; Siegel, N. P.; Toberer, E. S.; Ginley, D. S.

2016-05-01

We report on a new modular, dispatchable, and cost-effective solar electricity-generating technology. Solar ThermoElectricity via Advanced Latent heat Storage (STEALS) integrates several state-of-the-art technologies to provide electricity on demand. In the envisioned STEALS system, concentrated sunlight is converted to heat at a solar absorber. The heat is then delivered to either a thermoelectric (TE) module for direct electricity generation, or to charge a phase change material for thermal energy storage, enabling subsequent generation during off-sun hours, or both for simultaneous electricity production and energy storage. The key to making STEALS a dispatchable technology lies in the development of a "thermal valve," which controls when heat is allowed to flow through the TE module, thus controlling when electricity is generated. The current project addresses each of the three major subcomponents, (i) the TE module, (ii) the thermal energy storage system, and (iii) the thermal valve. The project also includes system-level and techno- economic modeling of the envisioned integrated system and will culminate in the demonstration of a laboratory-scale STEALS prototype capable of generating 3kWe.

Recent advances in the PV-CSP hybrid solar power technology

NASA Astrophysics Data System (ADS)

Ju, Xing; Xu, Chao; Han, Xue; Zhang, Hui; Wei, Gaosheng; Chen, Lin

2017-06-01

Photovoltaic - Concentrated Solar Power (PV-CSP) hybrid technology is considered to be an important future research trend in solar energy engineering. The development of the PV-CSP hybrid technology accelerates in recent years with the rapid maturation of photovoltaics (PV) and concentrated solar power (CSP). This paper presents the recent advances on PV-CSP technology, including different technologies based on new dispatch strategies, Organic Rankine Cycles, spectral beam filters and so on. The research status and the hybrid system performance of the recent researches are summarized, aimed to provide an extended recognition on the PV-CSP hybrid technology. The advantages and limitations of the hybrid system are concluded according to the researches reviewed.

The applications of Complexity Theory and Tsallis Non-extensive Statistics at Solar Plasma Dynamics

NASA Astrophysics Data System (ADS)

Pavlos, George

2015-04-01

As the solar plasma lives far from equilibrium it is an excellent laboratory for testing complexity theory and non-equilibrium statistical mechanics. In this study, we present the highlights of complexity theory and Tsallis non extensive statistical mechanics as concerns their applications at solar plasma dynamics, especially at sunspot, solar flare and solar wind phenomena. Generally, when a physical system is driven far from equilibrium states some novel characteristics can be observed related to the nonlinear character of dynamics. Generally, the nonlinearity in space plasma dynamics can generate intermittent turbulence with the typical characteristics of the anomalous diffusion process and strange topologies of stochastic space plasma fields (velocity and magnetic fields) caused by the strange dynamics and strange kinetics (Zaslavsky, 2002). In addition, according to Zelenyi and Milovanov (2004) the complex character of the space plasma system includes the existence of non-equilibrium (quasi)-stationary states (NESS) having the topology of a percolating fractal set. The stabilization of a system near the NESS is perceived as a transition into a turbulent state determined by self-organization processes. The long-range correlation effects manifest themselves as a strange non-Gaussian behavior of kinetic processes near the NESS plasma state. The complex character of space plasma can also be described by the non-extensive statistical thermodynamics pioneered by Tsallis, which offers a consistent and effective theoretical framework, based on a generalization of Boltzmann - Gibbs (BG) entropy, to describe far from equilibrium nonlinear complex dynamics (Tsallis, 2009). In a series of recent papers, the hypothesis of Tsallis non-extensive statistics in magnetosphere, sunspot dynamics, solar flares, solar wind and space plasma in general, was tested and verified (Karakatsanis et al., 2013; Pavlos et al., 2014; 2015). Our study includes the analysis of solar plasma time

Brayton advanced heat receiver development program

NASA Technical Reports Server (NTRS)

Heidenreich, G. R.; Downing, R. S.; Lacey, Dovie E.

1989-01-01

NASA Lewis Research Center is managing an advanced solar dynamic (ASD) space power program. The objective of the ASD program is to develop small and lightweight solar dynamic systems which show significant improvement in efficiency and specific mass over the baseline design derived from the Space Station Freedom technology. The advanced heat receiver development program is a phased program to design, fabricate and test elements of a 7-kWe heat-receiver/thermal-energy-storage subsystem. Receivers for both Brayton and Stirling heat engines are being developed under separate contracts. Phase I, described here, is the current eighteen month effort to design and perform critical technology experiments on innovative concepts designed to reduce mass without compromising thermal efficiency and reliability.

Aperture Shield Materials Characterized and Selected for Solar Dynamic Space Power System

NASA Technical Reports Server (NTRS)

1995-01-01

The aperture shield in a solar dynamic space power system is necessary to prevent thermal damage to the heat receiver should the concentrated solar radiation be accidentally or intentionally focused outside of the heat receiver aperture opening and onto the aperture shield itself. Characterization of the optical and thermal properties of candidate aperture shield materials was needed to support the joint U.S./Russian solar dynamic space power effort for Mir. The specific objective of testing performed at the NASA Lewis Research Center was to identify a high-temperature material with a low specular reflectance, a low solar absorptance, and a high spectral emittance so that during an off-pointing event, the amount of solar energy reflecting off the aperture shield would be small, the ratio of solar absorptance to spectral emittance would provide the lowest possible equilibrium temperature, and the integrity of the aperture shield would remain intact.

A Public-Private-Acadmic Partnership to Advance Solar Power Forecasting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haupt, Sue Ellen

The National Center for Atmospheric Research (NCAR) is pleased to have led a partnership to advance the state-of-the-science of solar power forecasting by designing, developing, building, deploying, testing, and assessing the SunCast™ Solar Power Forecasting System. The project has included cutting edge research, testing in several geographically- and climatologically-diverse high penetration solar utilities and Independent System Operators (ISOs), and wide dissemination of the research results to raise the bar on solar power forecasting technology. The partners include three other national laboratories, six universities, and industry partners. This public-private-academic team has worked in concert to perform use-inspired research to advance solarmore » power forecasting through cutting-edge research to advance both the necessary forecasting technologies and the metrics for evaluating them. The project has culminated in a year-long, full-scale demonstration of provide irradiance and power forecasts to utilities and ISOs to use in their operations. The project focused on providing elements of a value chain, beginning with the weather that causes a deviation from clear sky irradiance and progresses through monitoring and observations, modeling, forecasting, dissemination and communication of the forecasts, interpretation of the forecast, and through decision-making, which produces outcomes that have an economic value. The system has been evaluated using metrics developed specifically for this project, which has provided rich information on model and system performance. Research was accomplished on the very short range (0-6 hours) Nowcasting system as well as on the longer term (6-72 hour) forecasting system. The shortest range forecasts are based on observations in the field. The shortest range system, built by Brookhaven National Laboratory (BNL) and based on Total Sky Imagers (TSIs) is TSICast, which operates on the shortest time scale with a latency of only a

Advanced solar concentrator mass production, operation, and maintenance cost assessment

NASA Technical Reports Server (NTRS)

Niemeyer, W. A.; Bedard, R. J.; Bell, D. M.

1981-01-01

The object of this assessment was to estimate the costs of the preliminary design at: production rates of 100 to 1,000,000 concentrators per year; concentrators per aperture diameters of 5, 10, 11, and 15 meters; and various receiver/power conversion package weights. The design of the cellular glass substrate Advanced Solar Concentrator is presented. The concentrator is an 11 meter diameter, two axis tracking, parabolic dish solar concentrator. The reflective surface of this design consists of inner and outer groups of mirror glass/cellular glass gores.

Advanced Space Robotics and Solar Electric Propulsion: Enabling Technologies for Future Planetary Exploration

NASA Astrophysics Data System (ADS)

Kaplan, M.; Tadros, A.

2017-02-01

Obtaining answers to questions posed by planetary scientists over the next several decades will require the ability to travel further while exploring and gathering data in more remote locations of our solar system. Timely investments need to be made in developing and demonstrating solar electric propulsion and advanced space robotics technologies.

solar thermal power systems advanced solar thermal technology project, advanced subsystems development

NASA Technical Reports Server (NTRS)

1979-01-01

The preliminary design for a prototype small (20 kWe) solar thermal electric generating unit was completed, consisting of several subsystems. The concentrator and the receiver collect solar energy and a thermal buffer storage with a transport system is used to provide a partially smoothed heat input to the Stirling engine. A fossil-fuel combustor is included in the receiver designs to permit operation with partial or no solar insolation (hybrid). The engine converts the heat input into mechanical action that powers a generator. To obtain electric power on a large scale, multiple solar modules will be required to operate in parallel. The small solar electric power plant used as a baseline design will provide electricity at remote sites and small communities.

THE KEY ROLE OF SOLAR DYNAMICS IN THE CHROMOSPHERIC HANLE POLARIZATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carlin, E. S.; Bianda, M., E-mail: escarlin@irsol.ch

The quantum theory of polarized light allows one to model scattering in the solar atmosphere for inferring its properties. This powerful approach has revealed two key long-standing problems in solar physics: the puzzling dilemmas between theory and observations in several anomalously polarized spectral lines and the need for inferring the ubiquitous weak chromospheric magnetic fields, which requires discriminating the Hanle effect in dynamic optically thick plasmas. However, the ever-present dynamics, i.e., the temporal evolution of heatings and macroscopic motions, has been widely disregarded when modeling and interpreting the scattering polarization. This has hindered a consistent theoretical solution to the puzzlemore » while falsifying the Hanle diagnosis. Here, we show that the dynamical evolution is a keystone for solving both problems because its systematic impact allows an explanation of the observations from “anomalous” instantaneous polarization signals. Evolution accounted for, we reproduce amplitudes and (spectral and spatial) shapes of the Ca i 4227 Å polarization at solar disk center, identifying a restrictive arrangement of magnetic fields, kinematics, heatings, and spatio-temporal resolution. We find that the joint action of dynamics, Hanle effect, and low temporal resolutions mimics Zeeman linear polarization profiles, the true weak-field Zeeman signals being negligible. Our results allow reinterpretation of many polarization signals of the solar spectra and support time-dependent scattering polarization as a powerful tool for deciphering the spatio-temporal distribution of chromospheric heatings and fields. This approach may be a key aid in developing the Hanle diagnosis for the solar atmosphere.« less

NASA's Solar Dynamics Observatory Unveils New Images

NASA Image and Video Library

2017-12-08

Scientists presented the first images from NASA's Solar Dynamics Observatory [SDO] during a special "first light" press conference, Wednesday, April 21 2010, at held at the Newseum in Washington DC. Here, scientists are showing an animation from Walt Feimer, lead animator for the Heliophysics team. Credit: NASA/GSFC

Progress in the development of advanced solar reflectors

NASA Astrophysics Data System (ADS)

Kennedy, C.; Jorgensen, G.

1994-01-01

Solar thermal technologies require large mirrors to provide concentrated sunlight for renewable power generation. Such materials must be inexpensive and maintain high specular reflectance for extended lifetimes in severe outdoor environments. Polymer reflectors are lighter than glass mirrors, offer greater system design flexibility, and have the potential for lower cost. During the past year, collaborative cost-shared research and development between the National Renewable Energy Laboratory (NREL) and industrial partners has identified candidate materials that perform better than the state-of-the-art commercial silvered-polymer reflectors in terms of corrosion degradation and resistance to delamination failure. Additional cooperative efforts will produce new alternative materials with reduced costs due to high speed production line capability. NREL welcomes continued and expanded interest and web coating industry involvement in developing advanced solar reflector materials.

Mission applications for advanced photovoltaic solar arrays

NASA Technical Reports Server (NTRS)

Stella, Paul M.; West, John L.; Chave, Robert G.; Mcgee, David P.; Yen, Albert S.

1990-01-01

The suitability of the Advanced Photovoltaic Solar Array (APSA) for future space missions was examined by considering the impact on the spacecraft system in general. The lightweight flexible blanket array system was compared to rigid arrays and a radio-isotope thermoelectric generator (RTG) static power source for a wide range of assumed future earth orbiting and interplanetary mission applications. The study approach was to establish assessment criteria and a rating scheme, identify a reference mission set, perform the power system assessment for each mission, and develop conclusions and recommendations to guide future APSA technology development. The authors discuss the three selected power sources, the assessment criteria and rating definitions, and the reference missions. They present the assessment results in a convenient tabular format. It is concluded that the three power sources examined, APSA, conventional solar arrays, and RTGs, can be considered to complement each other. Each power technology has its own range of preferred applications.

Active Control of Solar Array Dynamics During Spacecraft Maneuvers

NASA Technical Reports Server (NTRS)

Ross, Brant A.; Woo, Nelson; Kraft, Thomas G.; Blandino, Joseph R.

2016-01-01

Recent NASA mission plans require spacecraft to undergo potentially significant maneuvers (or dynamic loading events) with large solar arrays deployed. Therefore there is an increased need to understand and possibly control the nonlinear dynamics in the spacecraft system during such maneuvers. The development of a nonlinear controller is described. The utility of using a nonlinear controller to reduce forces and motion in a solar array wing during a loading event is demonstrated. The result is dramatic reductions in system forces and motion during a 10 second loading event. A motion curve derived from the simulation with the closed loop controller is used to obtain similar benefits with a simpler motion control approach.

Multiscale Dynamics of Solar Magnetic Structures

NASA Technical Reports Server (NTRS)

Uritsky, Vadim M.; Davila, Joseph M.

2012-01-01

Multiscale topological complexity of the solar magnetic field is among the primary factors controlling energy release in the corona, including associated processes in the photospheric and chromospheric boundaries.We present a new approach for analyzing multiscale behavior of the photospheric magnetic flux underlying these dynamics as depicted by a sequence of high-resolution solar magnetograms. The approach involves two basic processing steps: (1) identification of timing and location of magnetic flux origin and demise events (as defined by DeForest et al.) by tracking spatiotemporal evolution of unipolar and bipolar photospheric regions, and (2) analysis of collective behavior of the detected magnetic events using a generalized version of the Grassberger-Procaccia correlation integral algorithm. The scale-free nature of the developed algorithms makes it possible to characterize the dynamics of the photospheric network across a wide range of distances and relaxation times. Three types of photospheric conditions are considered to test the method: a quiet photosphere, a solar active region (NOAA 10365) in a quiescent non-flaring state, and the same active region during a period of M-class flares. The results obtained show (1) the presence of a topologically complex asymmetrically fragmented magnetic network in the quiet photosphere driven by meso- and supergranulation, (2) the formation of non-potential magnetic structures with complex polarity separation lines inside the active region, and (3) statistical signatures of canceling bipolar magnetic structures coinciding with flaring activity in the active region. Each of these effects can represent an unstable magnetic configuration acting as an energy source for coronal dissipation and heating.

Complex-shaped solar sails: A study of the coupled attitude and trajectory dynamics

NASA Astrophysics Data System (ADS)

van de Kolk, Christel Brigitte

The concept of solar sailing is to reflect sunlight of a large surface in space to generate a low thrust, but constantly present, force. By varying the angle between sail normal and incident sunlight, a solar sail can fly inward (to the sun) and outward. The lifetime of a solar sail is not limited by the amount of fuel it can carry, since its fuel is sunlight. Degradation of the reflective surface, due to micrometeorite impact, etc, is the main limiting factor for the lifetime, but it is safe to say that the lifetime of a solar sail will be decades. This extensive lifetime and the possibility of inward and outward travel within the solar system, make solar sails good candidates for cargo missions within our solar system. They are less useful for manned flight, due to the long flight times of solar sail propelled vehicles. For example, the flight time from Earth to Mars is about a year. The solar sails studied previously were flat, single surfaces. The required stiffness and rigidity are provided by either a supporting structure or by spinning the sail. What both concepts have in common is that it was assumed that the attitude dynamics and trajectory dynamics were uncoupled. This assumption eliminates an entire family of promising flight modes in which the coupled motion provides automatic passive attitude dynamics and control. The research presented here will focus on the development of a full 3 dimensional model for the coupled attitude/trajectory dynamics problem of a complex shaped solar sail. This model will then be used to investigate the possible trajectory types and the stability of the attitude dynamics. It will be shown that it is possible to fly either inward to the Sun or out away from the Sun, depending on the dimensions of the individual sail planes and the angle between the two sail planes. However, passive attitude stability for all three axes will not be possible. The roll motion about the sail-sun line is unstable and some form of active control

Prompt Disappearance and Emergence of Radiation Belt Magnetosonic Waves Induced by Solar Wind Dynamic Pressure Variations

NASA Astrophysics Data System (ADS)

Liu, Nigang; Su, Zhenpeng; Zheng, Huinan; Wang, Yuming; Wang, Shui

2018-01-01

Magnetosonic waves are highly oblique whistler mode emissions transferring energy from the ring current protons to the radiation belt electrons in the inner magnetosphere. Here we present the first report of prompt disappearance and emergence of magnetosonic waves induced by the solar wind dynamic pressure variations. The solar wind dynamic pressure reduction caused the magnetosphere expansion, adiabatically decelerated the ring current protons for the Bernstein mode instability, and produced the prompt disappearance of magnetosonic waves. On the contrary, because of the adiabatic acceleration of the ring current protons by the solar wind dynamic pressure enhancement, magnetosonic waves emerged suddenly. In the absence of impulsive injections of hot protons, magnetosonic waves were observable even only during the time period with the enhanced solar wind dynamic pressure. Our results demonstrate that the solar wind dynamic pressure is an essential parameter for modeling of magnetosonic waves and their effect on the radiation belt electrons.

Advanced high efficiency wraparound contact solar cell

NASA Technical Reports Server (NTRS)

Scott-Monck, J. A.; Uno, F. M.; Thornhill, J. W.

1977-01-01

A significant advancement in the development of thin high efficiency wraparound contact silicon solar cells has been made by coupling space and terrestrial processing procedures. Although this new method for fabricating cells has not been completely reduced to practice, some of the initial cells have delivered over 20 mW/sq cm when tested at 25 C under AMO intensity. This approach not only yields high efficiency devices, but shows promise of allowing complete freedom of choice in both the location and size of the wraparound contact pad area.

Advanced high efficiency wraparound contact solar cell

NASA Technical Reports Server (NTRS)

Scott-Monck, J. A.; Uno, F. M.; Thornhill, J. W.

1977-01-01

A significant advancement in the development of thin high efficiency wraparound contact silicon solar cells has been made by coupling space and terrestrial processing procedures. Although this new method for fabricating cells has not been completely reduced to practice, some of the initial cells have delivered over 20 mW/sq cm when tested at 25 C under AMO intensity. This approach not only yields high efficiency devices, but shows promise of allowing complete freedom of choice in both the location and size of the wraparound contact pad area

2 kWe Solar Dynamic Ground Test Demonstration Project. Volume 1; Executive Summary

NASA Technical Reports Server (NTRS)

Alexander, Dennis

1997-01-01

The Solar Dynamic Ground Test Demonstration (SDGTD) successfully demonstrated a solar-powered closed Brayton cycle system in a relevant space thermal environment. In addition to meeting technical requirements the project was completed 4 months ahead of schedule and under budget. The following conclusions can be supported: 1. The component technology for solar dynamic closed Brayton cycle technology has clearly been demonstrated. 2. The thermal, optical, control, and electrical integration aspects of systems integration have also been successfully demonstrated. Physical integration aspects were not attempted as these tend to be driven primarily by mission-specific requirements. 3. System efficiency of greater than 15 percent (all losses fully accounted for) was demonstrated using equipment and designs which were not optimized. Some preexisting hardware was used to minimize cost and schedule. 4. Power generation of 2 kWe. 5. A NASA/industry team was developed that successfully worked together to accomplish project goals. The material presented in this report will show that the technology necessary to design and fabricate solar dynamic electrical power systems for space has been successfully developed and demonstrated. The data will further show that achieved results compare well with pretest predictions. The next step in the development of solar dynamic space power will be a flight test.

Solar Dynamic Power System Stability Analysis and Control

NASA Technical Reports Server (NTRS)

Momoh, James A.; Wang, Yanchun

1996-01-01

The objective of this research is to conduct dynamic analysis, control design, and control performance test of solar power system. Solar power system consists of generation system and distribution network system. A bench mark system is used in this research, which includes a generator with excitation system and governor, an ac/dc converter, six DDCU's and forty-eight loads. A detailed model is used for modeling generator. Excitation system is represented by a third order model. DDCU is represented by a seventh order system. The load is modeled by the combination of constant power and constant impedance. Eigen-analysis and eigen-sensitivity analysis are used for system dynamic analysis. The effects of excitation system, governor, ac/dc converter control, and the type of load on system stability are discussed. In order to improve system transient stability, nonlinear ac/dc converter control is introduced. The direct linearization method is used for control design. The dynamic analysis results show that these controls affect system stability in different ways. The parameter coordination of controllers are recommended based on the dynamic analysis. It is concluded from the present studies that system stability is improved by the coordination of control parameters and the nonlinear ac/dc converter control stabilize system oscillation caused by the load change and system fault efficiently.

NASA's Solar Dynamics Observatory Unveils New Images

NASA Image and Video Library

2010-04-20

Tom Woods, (second from right), principal investigator, Extreme Ultraviolet Variability Experiment instrument, Laboratory for Atmospheric and Space Physics, University of Colorado in Boulder speaks during a briefing to discuss recent images from NASA's Solar Dynamics Observatory, or SDO, Wednesday, April 21, 2010, at the Newseum in Washington. Photo Credit: (NASA/Carla Cioffi)

Solar dynamic power module design

NASA Technical Reports Server (NTRS)

Secunde, Richard R.; Labus, Thomas L.; Lovely, Ronald G.

1989-01-01

Studies have shown that use of solar dynamic (SD) power for the growth eras of the Space Station Freedom program will result in life cycle cost savings when compared to power supplied by photovoltaic sources. In the SD power module, a concentrator collects and focuses solar energy into a heat receiver which has integral thermal energy storage. A power conversion unit (PCU) based on the closed Brayton thermodynamic cycle removes thermal energy from the receiver and converts that energy to electrical energy. Since the closed Brayton cycle is a single phase gas cycle, the conversion hardware (heat exchangers, turbine, compressor, etc.) can be designed for operation in low earth orbit, and tested with confidence in test facilities on earth before launch into space. The concentrator subassemblies will be aligned and the receiver/PCU/radiator combination completely assembled and charged with gas and cooling liquid on earth before launch to, and assembly on orbit.

Control-structure interaction study for the Space Station solar dynamic power module

NASA Technical Reports Server (NTRS)

Cheng, J.; Ianculescu, G.; Ly, J.; Kim, M.

1991-01-01

The authors investigate the feasibility of using a conventional PID (proportional plus integral plus derivative) controller design to perform the pointing and tracking functions for the Space Station Freedom solar dynamic power module. Using this simple controller design, the control/structure interaction effects were also studied without assuming frequency bandwidth separation. From the results, the feasibility of a simple solar dynamic control solution with a reduced-order model, which satisfies the basic system pointing and stability requirements, is suggested. However, the conventional control design approach is shown to be very much influenced by the order of reduction of the plant model, i.e., the number of the retained elastic modes from the full-order model. This suggests that, for complex large space structures, such as the Space Station Freedom solar dynamic, the conventional control system design methods may not be adequate.

A program for advancing the technology of space concentrators

NASA Technical Reports Server (NTRS)

Naujokas, Gerald J.; Savino, Joseph M.

1989-01-01

In 1985, the NASA Lewis Research Center formed a project, the Advanced Solar Dynamics Power Systems Project, for the purpose of advancing the technology of Solar Dynamic Power Systems for space applications beyond 2000. Since then, technology development activities have been initiated for the major components and subsystems such as the concentrator, heat receiver and engine, and radiator. Described here is a program for developing long lived (10 years or more), lighter weight, and more reflective space solar concentrators than is presently possible. The program is progressing along two parallel paths: one is concentrator concept development and the other is the resolution of those critical technology issues that will lead to durable, highly specular, and lightweight reflector elements. Outlined are the specific objectives, long-term goals, approach, planned accomplishments for the future, and the present status of the various program elements.

A program for advancing the technology of space concentrators

NASA Technical Reports Server (NTRS)

Naujokas, Gerald J.; Savino, Joseph M.

1989-01-01

In 1985, the NASA Lewis Research Center formed a project, the Advanced Solar Dynamics Power Systems Project, for the purpose of advancing the technology of Solar Dynamic Power Systems for space applications beyond 2000. Since then, technology development activities have been initiated for the major components and subsystems such as the concentrator, heat receiver and engine, and radiator. Described here is a program for developing long lived (10 years or more), lighter weight, and more reflective space solar concentrators than is presently possible. The program is progressing along two parallel paths: one is concentrator concept development and the other is the resolution of those critical technology issues that will lead to durable, highly specular, and lightweight reflector elements. Outlined are the specific objectives, long term goals, approach, planned accomplishments for the future, and the present status of the various program elements.

Attitude Dynamics, Stability, and Control of a Heliogyro Solar Sail

NASA Astrophysics Data System (ADS)

Pimienta-Penalver, Adonis Reinier

A heliogyro solar sail concept, dubbed `HELIOS', is proposed as an alternative to deep space missions without the need for on-board propellant. Although this type of solar sail has existed in concept for several decades, and some previous studies have investigated certain aspects of its operation, a significant amount of research is still needed to analyze the dynamic and control characteristics of the structure under the projected range of orbital conditions. This work presents an improvement upon the existing discrete-mass models of the heliogyro blade, and the extension of its application from a single membrane blade to a fully-coupled approximation of the dynamics of the HELIOS system with multiple spinning membrane blades around a central hub. The incorporation of structural stiffness and external forcing effects into the model is demonstrated to add a further degree of fidelity in simulating the stability properties of the system. Additionally, the approximated dynamics of multiple-blade heliogyro structures are examined under the effect of solar radiation pressure. Lastly, this study evaluates a control algorithm at each blade root to impose structural integrity and attitude control by coordinating well-known helicopter blade pitching profiles.

Dynamics of Solar Energetic Particles in the Presence of a Shock Wave

NASA Astrophysics Data System (ADS)

Timofeev, V. E.; Petukhov, Ivan; Petukhov, Stanislav; Starodubtsev, Sergei

2003-07-01

From the analysis of problem solutions on the solar energetic particle propagation in the presence of a plane shock wave described by the diffusion convective transport equation, the condition and manifestations for the influence of a shock wave on the SEP propagation in the solar wind have been determined. Solar energetic particles (SEP) in gradual events are generated by shock waves (see, for example, [1] and references there). The SEP generation region is limited, on the whole, by the solar corona. Proton fluxes of 470 MeV to 21 GeV energies, a maximum of which occur at a time when the shock in the atmosphere of the Sun reaches heights equal to 5 10 solar radii [2] indicate to it. It is also confirmed by the significant advancing of the occurrence time of maximum in the SEP intensity with kinetic energies more than 10 MeV relative to the shock front arrival moment to Earth's orbit. model calculations for the particles acceleration by the diffusive mechanism in conditions, typical for the solar corona, show that the time taken to pass the solar atmosphere by the shock is quite sufficient to form the particle spectrum corresponding to the SEP characteristics observed [3,4]. Lee and Ryan [5] investigated the problem of SEP gradual event generation, propagation and confirmed the close association between the diffusive acceleration mechanism and SEP events. The absence of depending of particle diffusion coefficients on the energy is a lack of this model. As an extension of preceding investigations, in this work the temporal dynamics of the particle spectrum in the presence of a plane shock for diffusion coefficients depending on the particle energy and also their change in time is studied. The SEP event from a moment of arising of a shock to a moment of it's arrival on the Earth's orbit can be divided on two stages: the first stage (duration is ˜ 1 hour) is a generation of SEP in the solar corona, the second stage (duration is ˜ 1 day) is a propagation in

Preface: MHD wave phenomena in the solar interior and atmosphere

NASA Astrophysics Data System (ADS)

Fedun, Viktor; Srivastava, A. K.

2018-01-01

The Sun is our nearest star and this star produces various plasma wave processes and energetic events. These phenomena strongly influence interplanetary plasma dynamics and contribute to space-weather. The understanding of solar atmospheric dynamics requires hi-resolution modern observations which, in turn, further advances theoretical models of physical processes in the solar interior and atmosphere. In particular, it is essential to connect the magnetohydrodynamic (MHD) wave processes with the small and large-scale solar phenomena vis-a-vis transport of energy and mass. With the advent of currently available and upcoming high-resolution space (e.g., IRIS, SDO, Hinode, Aditya-L1, Solar-C, Solar Orbiter), and ground-based (e.g., SST, ROSA, NLST, Hi-C, DKIST, EST, COSMO) observations, solar physicists are able to explore exclusive wave processes in various solar magnetic structures at different spatio-temporal scales.

Advanced Solar Cell and Array Technology for NASA Deep Space Missions

NASA Technical Reports Server (NTRS)

Piszczor, Michael; Benson, Scott; Scheiman, David; Finacannon, Homer; Oleson, Steve; Landis, Geoffrey

2008-01-01

A recent study by the NASA Glenn Research Center assessed the feasibility of using photovoltaics (PV) to power spacecraft for outer planetary, deep space missions. While the majority of spacecraft have relied on photovoltaics for primary power, the drastic reduction in solar intensity as the spacecraft moves farther from the sun has either limited the power available (severely curtailing scientific operations) or necessitated the use of nuclear systems. A desire by NASA and the scientific community to explore various bodies in the outer solar system and conduct "long-term" operations using using smaller, "lower-cost" spacecraft has renewed interest in exploring the feasibility of using photovoltaics for to Jupiter, Saturn and beyond. With recent advances in solar cell performance and continuing development in lightweight, high power solar array technology, the study determined that photovoltaics is indeed a viable option for many of these missions.

Optimization of an Advanced Multi-Junction Solar-Cell Design for Space Environments (AM0) Using Nearly Orthogonal Latin Hypercubes

DTIC Science & Technology

2017-06-01

AN ADVANCED MULTI-JUNCTION SOLAR -CELL DESIGN FOR SPACE ENVIRONMENTS (AM0) USING NEARLY ORTHOGONAL LATIN HYPERCUBES by Silvio Pueschel June...ADVANCED MULTI-JUNCTION SOLAR -CELL DESIGN FOR SPACE ENVIRONMENTS (AM0) USING NEARLY ORTHOGONAL LATIN HYPERCUBES 5. FUNDING NUMBERS 6. AUTHOR(S) Silvio...multi-junction solar cells with Silvaco Atlas simulation software. It introduces the nearly orthogonal Latin hypercube (NOLH) design of experiments (DoE

Modeling the Multi-Body System Dynamics of a Flexible Solar Sail Spacecraft

NASA Technical Reports Server (NTRS)

Kim, Young; Stough, Robert; Whorton, Mark

2005-01-01

Solar sail propulsion systems enable a wide range of space missions that are not feasible with current propulsion technology. Hardware concepts and analytical methods have matured through ground development to the point that a flight validation mission is now realizable. Much attention has been given to modeling the structural dynamics of the constituent elements, but to date an integrated system level dynamics analysis has been lacking. Using a multi-body dynamics and control analysis tool called TREETOPS, the coupled dynamics of the sailcraft bus, sail membranes, flexible booms, and control system sensors and actuators of a representative solar sail spacecraft are investigated to assess system level dynamics and control issues. With this tool, scaling issues and parametric trade studies can be performed to study achievable performance, control authority requirements, and control/structure interaction assessments.

Solar terrestrial observatory

NASA Technical Reports Server (NTRS)

1981-01-01

Eight basic solar-terrestrial scientific objectives that benefit from the Shuttle/Platform approach and a program of measurements for each are discussed. The objectives are to understand: (1) solar variability, (2) wave-particle processes, (3) magnetosphere-ionosphere mass transport, (4) the global electric circuit, (5) upper atmospheric dynamics, (6) middle atmospheric chemistry and energetics, (7) lower atmospheric turbidity, and (8) planetary atmospheric waves. A two stage approach to a multidisciplinary payload is developed: an initial STO, that uses a single platform in a low-Earth orbit, and an advanced STO that uses two platforms in differing orbits.

CORONAL DYNAMIC ACTIVITIES IN THE DECLINING PHASE OF A SOLAR CYCLE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jang, Minhwan; Choe, G. S.; Woods, T. N.

2016-12-10

It has been known that some solar activity indicators show a double-peak feature in their evolution through a solar cycle, which is not conspicuous in sunspot number. In this Letter, we investigate the high solar dynamic activity in the declining phase of the sunspot cycle by examining the evolution of polar and low-latitude coronal hole (CH) areas, splitting and merging events of CHs, and coronal mass ejections (CMEs) detected by SOHO /LASCO C3 in solar cycle 23. Although the total CH area is at its maximum near the sunspot minimum, in which polar CHs prevail, it shows a comparable secondmore » maximum in the declining phase of the cycle, in which low-latitude CHs are dominant. The events of CH splitting or merging, which are attributed to surface motions of magnetic fluxes, are also mostly populated in the declining phase of the cycle. The far-reaching C3 CMEs are also overpopulated in the declining phase of the cycle. From these results we suggest that solar dynamic activities due to the horizontal surface motions of magnetic fluxes extend far in the declining phase of the sunspot cycle.« less

Solar Power Satellite Development: Advances in Modularity and Mechanical Systems

NASA Technical Reports Server (NTRS)

Belvin, W. Keith; Dorsey, John T.; Watson, Judith J.

2010-01-01

Space solar power satellites require innovative concepts in order to achieve economically and technically feasible designs. The mass and volume constraints of current and planned launch vehicles necessitate highly efficient structural systems be developed. In addition, modularity and in-space deployment will be enabling design attributes. This paper reviews the current challenges of launching and building very large space systems. A building block approach is proposed in order to achieve near-term solar power satellite risk reduction while promoting the necessary long-term technology advances. Promising mechanical systems technologies anticipated in the coming decades including modularity, material systems, structural concepts, and in-space operations are described

NASA's Solar Dynamics Observatory Unveils New Images

NASA Image and Video Library

2010-04-20

Madhulika Guhathakurta, far right, SDO Program Scientist at NASA Headquarters in Washington, speaks during a briefing to discuss recent images from NASA's Solar Dynamics Observatory, or SDO, Wednesday, April 21, 2010, at the Newseum in Washington. Pictured from left of Dr. Guhathakurta's are: Tom Woods, principal investigator, Extreme Ultraviolet Variability Experiment instrument, Laboratory for Atmospheric and Space Physics, University of Colorado in Boulder; Philip H. Scherrer, principal investigator, Helioseismic and Magnetic Imager instrument, Stanford University in Palo Alto; Alan Title, principal investigator, Atmospheric Imaging Assembly instrument, Lockheed Martin Solar and Astrophysics Laboratory in Palo Alto and Dean Pesnell, SDO project scientist, Goddard Space Flight Center in Greenbelt, Md. Photo Credit: (NASA/Carla Cioffi)

NASA's Solar Dynamics Observatory Unveils New Images

NASA Image and Video Library

2010-04-20

Scientists involved in NASA's Solar Dynamics Observatory (SDO) mission attend a press conference to discuss recent images captured by the SDO spacecraft Wednesday, April 21, 2010, at the Newseum in Washington. Pictured right to left are: Madhulika Guhathakurta, SDO program scientist, NASA Headquarters in Washington; Tom Woods, principal investigator, Extreme Ultraviolet Variability Experiment instrument, Laboratory for Atmospheric and Space Physics, University of Colorado in Boulder; Philip H. Scherrer, principal investigator, Helioseismic and Magnetic Imager instrument, Stanford University in Palo Alto; Alan Title, principal investigator, Atmospheric Imaging Assembly instrument, Lockheed Martin Solar and Astrophysics Laboratory in Palo Alto and Dean Pesnell, SDO project scientist, Goddard Space Flight Center in Greenbelt, Md. Photo Credit: (NASA/Carla Cioffi)

Advanced photovoltaic solar array - Design and performance

NASA Technical Reports Server (NTRS)

Kurland, Richard; Stella, Paul

1992-01-01

This paper reports on the development of an ultralightweight flexible blanket, flatpack, foldout solar array design that can provide 3- to 4-fold improvement on specific power performance of current rigid panel arrays and a factor of two improvement over a first-generation flexible blanket array developed as a forerunner to the Space Station Freedom array. To date a prototype wing has been built with a projected specific power performance of about 138 W/kg at beginning-of-life (BOL) and 93 W/kg end-of-life (EOL) at 12 kW (BOL) for a 10-year geosynchronous (GEO) mission. The prototype wing hardware has been subjected to a series of system-level tests to demonstrate design feasibility. The design of the array is summarized. The major trade studies that led to the selection of the baseline design are discussed. Key system-level and component-level testing are described. Array-level performance projections are presented as a function of existing and advanced solar array component technology for various mission applications.

Advanced Rainbow Solar Photovoltaic Arrays

NASA Technical Reports Server (NTRS)

Mardesich, Nick; Shields, Virgil

2003-01-01

Photovoltaic arrays of the rainbow type, equipped with light-concentrator and spectral-beam-splitter optics, have been investigated in a continuing effort to develop lightweight, high-efficiency solar electric power sources. This investigation has contributed to a revival of the concept of the rainbow photovoltaic array, which originated in the 1950s but proved unrealistic at that time because the selection of solar photovoltaic cells was too limited. Advances in the art of photovoltaic cells since that time have rendered the concept more realistic, thereby prompting the present development effort. A rainbow photovoltaic array comprises side-by-side strings of series-connected photovoltaic cells. The cells in each string have the same bandgap, which differs from the bandgaps of the other strings. Hence, each string operates most efficiently in a unique wavelength band determined by its bandgap. To obtain maximum energy-conversion efficiency and to minimize the size and weight of the array for a given sunlight input aperture, the sunlight incident on the aperture is concentrated, then spectrally dispersed onto the photovoltaic array plane, whereon each string of cells is positioned to intercept the light in its wavelength band of most efficient operation. The number of cells in each string is chosen so that the output potentials of all the strings are the same; this makes it possible to connect the strings together in parallel to maximize the output current of the array. According to the original rainbow photovoltaic concept, the concentrated sunlight was to be split into multiple beams by use of an array of dichroic filters designed so that each beam would contain light in one of the desired wavelength bands. The concept has since been modified to provide for dispersion of the spectrum by use of adjacent prisms. A proposal for an advanced version calls for a unitary concentrator/ spectral-beam-splitter optic in the form of a parabolic curved Fresnel-like prism

Recent advances in satellite observations of solar variability and global atmospheric ozone

NASA Technical Reports Server (NTRS)

Heath, D. F.

1974-01-01

A description is given of the temporal behavior of the sun as an ultraviolet variable star in relation to daily zonal means of atmospheric ozone from the total amount to that above the 10-mb and 4-mb pressure levels. A significant correlation has been observed between enhancements in the ultraviolet solar irradiances and terrestrial passages of the solar magnetic field sector boundary structure. However, it has not yet been possible to separate solar from the dynamical effects on the variability in the zonal means of ozone. Attention is given to global changes in ozone which have been derived from the satellite observations in terms of season, solar variability, and major stratospheric disturbances such as stratospheric warmings.

Use of Advanced Solar Cells for Commercial Communication Satellites

NASA Technical Reports Server (NTRS)

Bailey, Sheila G.; Landis, Geoffrey A.

1995-01-01

The current generation of communications satellites are located primarily in geosynchronous Earth orbit (GEO). Over the next decade, however, a new generation of communications satellites will be built and launched, designed to provide a world-wide interconnection of portable telephones. For this mission, the satellites must be positioned in lower polar and near-polar orbits. To provide complete coverage, large numbers of satellites will be required. Because the required number of satellites decreases as the orbital altitude is increased, fewer satellites would be required if the orbit chosen were raised from low to intermediate orbit. However, in intermediate orbits, satellites encounter significant radiation due to trapped electrons and protons. Radiation tolerant solar cells may be necessary to make such satellites feasible. We analyze the amount of radiation encountered in low and intermediate polar orbits at altitudes of interest to next-generation communication satellites, calculate the expected degradation for silicon, GaAs, and InP solar cells, and show that the lifetimes can be significantly increased by use of advanced solar cells.

Use of advanced solar cells for commerical communication satellites

NASA Astrophysics Data System (ADS)

Landis, Geoffrey A.; Bailey, Sheila G.

1995-01-01

The current generation of communications satellites are located primarily in geosynchronous Earth orbit (GEO). Over the next decade, however, a new generation of communications satellites will be built and launched, designed to provide a world-wide interconnection of portable telephones. For this mission, the satellites must be positioned in lower polar- and near-polar orbits. To provide complete coverage, large numbers of satellites will be required. Because of the required number of satellites decreases as the orbital altitude is increased, fewer satellites would be required if the orbit chosen were raised from Low to intermediate orbit. However, in intermediate orbits, satellites encounter significant radiation due to trapped electrons and protons. Radiation tolerant solar cells may be necessary to make such satellites feasible. We analyze the amount of radiation encountered in low and intermediate polar orbits at altitudes of interest to next-generation communication satellites, calculate the expected degradation for silicon, GaAs, and InP solar cells, and show that the lifetimes can be significantly increased by use of advanced solar cells.

Use of advanced solar cells for commercial communication satellites

NASA Astrophysics Data System (ADS)

Bailey, Sheila G.; Landis, Geoffrey A.

1995-03-01

The current generation of communications satellites are located primarily in geosynchronous Earth orbit (GEO). Over the next decade, however, a new generation of communications satellites will be built and launched, designed to provide a world-wide interconnection of portable telephones. For this mission, the satellites must be positioned in lower polar and near-polar orbits. To provide complete coverage, large numbers of satellites will be required. Because the required number of satellites decreases as the orbital altitude is increased, fewer satellites would be required if the orbit chosen were raised from low to intermediate orbit. However, in intermediate orbits, satellites encounter significant radiation due to trapped electrons and protons. Radiation tolerant solar cells may be necessary to make such satellites feasible. We analyze the amount of radiation encountered in low and intermediate polar orbits at altitudes of interest to next-generation communication satellites, calculate the expected degradation for silicon, GaAs, and InP solar cells, and show that the lifetimes can be significantly increased by use of advanced solar cells.

Power output and carrier dynamics studies of perovskite solar cells under working conditions.

PubMed

Yu, Man; Wang, Hao-Yi; Hao, Ming-Yang; Qin, Yujun; Fu, Li-Min; Zhang, Jian-Ping; Ai, Xi-Cheng

2017-08-02

Perovskite solar cells have emerged as promising photovoltaic systems with superb power conversion efficiency. For the practical application of perovskite devices, the greatest concerns are the power output density and the related dynamics under working conditions. In this study, the working conditions of planar and mesoscopic perovskite solar cells are simulated and the power output density evolutions with the working voltage are highlighted. The planar device exhibits higher capability of outputting power than the mesoscopic one. The transient photoelectric conversion dynamics are investigated under the open circuit, short circuit and working conditions. It is found that the power output and dynamic processes are correlated intrinsically, which suggests that the power output is the competitive result of the charge carrier recombination and transport. The present work offers a unique view to elucidating the relationship between the power output and the charge carrier dynamics for perovskite solar cells in a comprehensive manner, which would be beneficial to their future practical applications.

Advanced Receiver tracking of Voyager 2 near solar conjunction

NASA Technical Reports Server (NTRS)

Brown, D. H.; Hurd, W. J.; Vilnrotter, V. A.; Wiggins, J. D.

1988-01-01

The Advanced Receiver (ARX) was used to track the Voyager 2 spacecraft at low Sun-Earth-Probe (SEP) angles near solar conjunction in December of 1987. The received carrier signal exhibited strong fluctuations in both phase and amplitude. The ARX used spectral estimation and mathematical modeling of the phase and receiver noise processes to set an optimum carrier tracking bandwidth. This minimized the mean square phase error in tracking carrier phase and thus minimized the loss in the telemetry signal-to-noise ratio due to the carrier loop. Recovered symbol SNRs and errors in decoded engineering data for the ARX are compared with those for the current Block 3 telemetry stream. Optimum bandwidths are plotted against SEP angle. Measurements of the power spectral density of the solar phase and amplitude fluctuations are also given.

Analysis of Solar Receiver Flux Distributions for US/Russian Solar Dynamic System Demonstration on the MIR Space Station

NASA Technical Reports Server (NTRS)

1995-01-01

Analyses have been performed at the NASA Lewis Research Center's Power Systems Project Office to support the design and development of the joint U.S./Russian Solar Dynamic Flight Demonstration Project. The optical analysis of the concentrator and solar flux predictions on target receiver surfaces have an important influence on receiver design and control of the Brayton engine.

Strong Solar Wind Dynamic Pressure Pulses during Solar Cycle 23 and Their Impacts on Geosynchronous Magnetic Fields

NASA Astrophysics Data System (ADS)

Zuo, P.

2015-12-01

Solar wind dynamic pressure pulse (DPP) structures, across which the dynamic pressure abruptly changes over timescales from a few seconds to several minutes, are often observed in the near-Earth space environment. In this investigation, we first present a statistical study on the properties of strong dynamic pressure pulses in the solar wind during solar cycle 23. It is found that overwhelming majority of DPPs are associated with the solar wind disturbances including the CME-related flows, the corotating interaction regions, as well as the complex ejecta. The annual variations of the averaged occurrence rate of DPPs are roughly in phase with the solar activities. Although the variabilities of geosynchronous magnetic fields (GMFs) due to the impact of positive DPPs have been well established, there appears no systematic investigations on the response of GMFs to negative DPPs. Here we also study the decompression/compression effects of very strong negative/positive DPPs on GMFs under northward IMFs. In response to the decompression of strong negative DPPs, GMFs on dayside, near the dawn and dusk on nightside are generally depressed. But near the midnight region, the responses of GMF are very diverse, being either positive or negative. For part of events when GOES is located at the midnight sector, GMF is found to abnormally increase as the result of magnetospheric decompression caused by negative DPPs. It is known that on certain conditions magnetic depression of nightside GMFs can be caused by the impact of positive DPPs. Here we found that, a stronger pressure enhancement may have a higher probability of producing the exceptional depression of GMF at midnight region. Statistically, both the decompression effect of strong negative DPPs and the compression effect of strong positive DPPs depend on the magnetic local time, being stronger at the noon sector.

The solar cycle; Proceedings of the National Solar Observatory/Sacramento Peak 12th Summer Workshop, Sunspot, NM, Oct. 15-18, 1991

NASA Technical Reports Server (NTRS)

Harvey, Karen L. (Editor)

1992-01-01

Attention is given to a flux-transport model, the effect of fractal distribution on the evolution of solar surface magnetic fields, active nests on the sun, magnetic flux transport in solar active regions, recent advances in stellar cycle research, magnetic intermittency on the sun, a search for existence of large-scale motions on the sun, and new solar cycle data from the NASA/NSO spectromagnetograph. Attention is also given to the solar cycle variation of coronal temperature during cycle 22, the distribution of the north-south asymmetry for the various activity cycles, solar luminosity variation, a two-parameter model of total solar irradiance variation over the solar cycle, the origin of the solar cycle, nonlinear feedbacks in the solar dynamo, and long-term dynamics of the solar cycle.

Closed Cycle Engine Program Used in Solar Dynamic Power Testing Effort

NASA Technical Reports Server (NTRS)

Ensworth, Clint B., III; McKissock, David B.

1998-01-01

NASA Lewis Research Center is testing the world's first integrated solar dynamic power system in a simulated space environment. This system converts solar thermal energy into electrical energy by using a closed-cycle gas turbine and alternator. A NASA-developed analysis code called the Closed Cycle Engine Program (CCEP) has been used for both pretest predictions and post-test analysis of system performance. The solar dynamic power system has a reflective concentrator that focuses solar thermal energy into a cavity receiver. The receiver is a heat exchanger that transfers the thermal power to a working fluid, an inert gas mixture of helium and xenon. The receiver also uses a phase-change material to store the thermal energy so that the system can continue producing power when there is no solar input power, such as when an Earth-orbiting satellite is in eclipse. The system uses a recuperated closed Brayton cycle to convert thermal power to mechanical power. Heated gas from the receiver expands through a turbine that turns an alternator and a compressor. The system also includes a gas cooler and a radiator, which reject waste cycle heat, and a recuperator, a gas-to-gas heat exchanger that improves cycle efficiency by recovering thermal energy.

Dynamics of Intense Currents in the Solar Wind

NASA Astrophysics Data System (ADS)

Artemyev, Anton V.; Angelopoulos, Vassilis; Halekas, Jasper S.; Vinogradov, Alexander A.; Vasko, Ivan Y.; Zelenyi, Lev M.

2018-06-01

Transient currents in the solar wind are carried by various magnetic field discontinuities that contribute significantly to the magnetic field fluctuation spectrum. Internal instabilities and dynamics of these discontinuities are believed to be responsible for magnetic field energy dissipation and corresponding charged particle acceleration and heating. Accurate modeling of these phenomena requires detailed investigation of transient current formation and evolution. By examining such evolution using a unique data set compiled from observations of the same solar wind flow by two spacecraft at Earth’s and Mars’s orbits, we show that it consists of several processes: discontinuity thinning (decrease in thickness normalized by the ion inertial length), intensification of currents normalized to the proton thermal current (i.e., the product of proton charge, density, and thermal velocity), and increase in the compressional component of magnetic field variations across discontinuities. The significant proton temperature variation around most observed discontinuities indicates possible proton heating. Plasma velocity jumps across the discontinuities are well correlated with Alfvén velocity changes. We discuss possible explanations of the observed discontinuity evolution. We also compare the observed evolution with predictions of models describing discontinuity formation due to Alfvén wave steepening. Our results show that discontinuity modeling likely requires taking into account both the effects of nonlinear Alfvén wave dynamics and solar wind expansion.

Dynamic conversion of solar generated heat to electricity

NASA Technical Reports Server (NTRS)

Powell, J. C.; Fourakis, E.; Hammer, J. M.; Smith, G. A.; Grosskreutz, J. C.; Mcbride, E.

1974-01-01

The effort undertaken during this program led to the selection of the water-superheated steam (850 psig/900 F) crescent central receiver as the preferred concept from among 11 candidate systems across the technological spectrum of the dynamic conversion of solar generated heat to electricity. The solar power plant designs were investigated in the range of plant capacities from 100 to 1000 Mw(e). The investigations considered the impacts of plant size, collector design, feed-water temperature ratio, heat rejection equipment, ground cover, and location on solar power technical and economic feasibility. For the distributed receiver systems, the optimization studies showed that plant capacities less than 100 Mw(e) may be best. Although the size of central receiver concepts was not parametrically investigated, all indications are that the optimal plant capacity for central receiver systems will be in the range from 50 to 200 Mw(e). Solar thermal power plant site selection criteria and methodology were also established and used to evaluate potentially suitable sites. The result of this effort was to identify a site south of Inyokern, California, as typically suitable for a solar thermal power plant. The criteria used in the selection process included insolation and climatological characteristics, topography, and seismic history as well as water availability.

Effects Investigated of Ambient High-Temperature Exposure on Alumina-Titania High-Emittance Surfaces for Solar Dynamic Systems

NASA Technical Reports Server (NTRS)

deGroh, Kim K.; Smith, Daniela C.

1999-01-01

Solar-dynamic space power systems require durable, high-emittance surfaces on a number of critical components, such as heat receiver interior surfaces and parasitic load radiator (PLR) elements. An alumina-titania coating, which has been evaluated for solar-dynamic heat receiver canister applications, has been chosen for a PLR application (an electrical sink for excess power from the turboalternator/compressor) because of its demonstrated high emittance and high-temperature durability in vacuum. Under high vacuum conditions (+/- 10(exp -6) torr), the alumina-titania coating was found to be durable at temperatures of 1520 F (827 C) for approx. 2700 hours with no degradation in optical properties. This coating has been successfully applied to the 2-kW solar-dynamic ground test demonstrator at the NASA Lewis Research Center, to the 500 thermal-energy-storage containment canisters inside the heat receiver and to the PLR radiator. The solar-dynamic demonstrator has successfully operated for over 800 hours in Lewis large thermal/vacuum space environment facility, demonstrating the feasibility of solar-dynamic power generation for space applications.

Generic solar photovoltaic system dynamic simulation model specification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ellis, Abraham; Behnke, Michael Robert; Elliott, Ryan Thomas

This document is intended to serve as a specification for generic solar photovoltaic (PV) system positive-sequence dynamic models to be implemented by software developers and approved by the WECC MVWG for use in bulk system dynamic simulations in accordance with NERC MOD standards. Two specific dynamic models are included in the scope of this document. The first, a Central Station PV System model, is intended to capture the most important dynamic characteristics of large scale (> 10 MW) PV systems with a central Point of Interconnection (POI) at the transmission level. The second, a Distributed PV System model, is intendedmore » to represent an aggregation of smaller, distribution-connected systems that comprise a portion of a composite load that might be modeled at a transmission load bus.« less

Considering Planetary Constraints and Dynamic Screening in Solar Evolution Modeling

NASA Astrophysics Data System (ADS)

Wood, Suzannah R.; Mussack, Katie; Guzik, Joyce A.

2018-01-01

The ‘faint early sun problem’ remains unsolved. This problem consists of the apparent contradiction between the standard solar model prediction of lower luminosity (70% of current luminosity) and the observations of liquid water on early Earth and Mars. The presence of liquid water on early Earth and Mars should not be neglected and should be used as a constraint for solar evolution modeling. In addition, modifications to standard solar models are needed to address the discrepancy with solar structure inferred from helioseismology given the latest solar abundance determinations. Here, we will utilize the three different solar abundances: GN93 (Grevesse & Noels, 1993), AGS05 (Asplund et al., 2005), AGSS09 (Asplund et al., 2009). Here, we propose an early mass loss model with an initial solar mass between 1.07 and 1.15 solar masses and an exponentially decreasing mass-loss rate to meet conditions in the early solar system (Wood et al, submitted). Additionally, we investigate the effects of dynamic screening and the new OPLIB opacities from Los Alamos (Colgan et al., 2016). We show the effects of these modifications to the standard solar evolution models on the interior structure, neutrino fluxes, sound speed, p-mode frequencies, convection zone depth, and envelope helium and element abundance of the model sun at the present day.

Greening the Grid - Advancing Solar, Wind, and Smart Grid Technologies (Spanish Version)

DOE Office of Scientific and Technical Information (OSTI.GOV)

This is the Spanish version of 'Greening the Grid - Advancing Solar, Wind, and Smart Grid Technologies'. Greening the Grid provides technical assistance to energy system planners, regulators, and grid operators to overcome challenges associated with integrating variable renewable energy into the grid.

Lightweight Phase-Change Material For Solar Power

NASA Technical Reports Server (NTRS)

Stark, Philip

1993-01-01

Lightweight panels containing phase-change materials developed for use as heat-storage elements of compact, lightweight, advanced solar dynamic power system. During high insolation, heat stored in panels via latent heat of fusion of phase-change material; during low insolation, heat withdrawn from panels. Storage elements consist mainly of porous carbon-fiber structures imbued with germanium. Developed for use aboard space station in orbit around Earth, also adapted to lightweight, compact, portable solar-power systems for use on Earth.

The Structure and Dynamics of the Solar Corona and Inner Heliosphere

NASA Technical Reports Server (NTRS)

Mikic, Zoran

2002-01-01

This report covers technical progress during the second quarter of the first year of NASA Sun-Earth Connections Theory Program (SECTP) contract 'The Structure and Dynamics of the Solar Corona and Inner Heliosphere,' NAS5-99188, between NASA and Science Applications International Corporation. and covers the period November 16, 1999 to February 15, 2000. Under this contract SAIC and the University of California, Irvine (UCI) have conducted research into theoretical modeling of active regions, the solar corona, and the inner heliosphere, using the MHD (magnetohydrodynamic) model. The topics studied include: the effect of emerging flux on the stability of helmet streamers, coronal loops and streamers, the solar magnetic field, the solar wind, and open magnetic field lines.

Solar Activity Across the Scales: From Small-Scale Quiet-Sun Dynamics to Magnetic Activity Cycles

NASA Technical Reports Server (NTRS)

Kitiashvili, Irina N.; Collins, Nancy N.; Kosovichev, Alexander G.; Mansour, Nagi N.; Wray, Alan A.

2017-01-01

Observations as well as numerical and theoretical models show that solar dynamics is characterized by complicated interactions and energy exchanges among different temporal and spatial scales. It reveals magnetic self-organization processes from the smallest scale magnetized vortex tubes to the global activity variation known as the solar cycle. To understand these multiscale processes and their relationships, we use a two-fold approach: 1) realistic 3D radiative MHD simulations of local dynamics together with high resolution observations by IRIS, Hinode, and SDO; and 2) modeling of solar activity cycles by using simplified MHD dynamo models and mathematical data assimilation techniques. We present recent results of this approach, including the interpretation of observational results from NASA heliophysics missions and predictive capabilities. In particular, we discuss the links between small-scale dynamo processes in the convection zone and atmospheric dynamics, as well as an early prediction of Solar Cycle 25.

Solar activity across the scales: from small-scale quiet-Sun dynamics to magnetic activity cycles

NASA Astrophysics Data System (ADS)

Kitiashvili, I.; Collins, N.; Kosovichev, A. G.; Mansour, N. N.; Wray, A. A.

2017-12-01

Observations as well as numerical and theoretical models show that solar dynamics is characterized by complicated interactions and energy exchanges among different temporal and spatial scales. It reveals magnetic self-organization processes from the smallest scale magnetized vortex tubes to the global activity variation known as the solar cycle. To understand these multiscale processes and their relationships, we use a two-fold approach: 1) realistic 3D radiative MHD simulations of local dynamics together with high-resolution observations by IRIS, Hinode, and SDO; and 2) modeling of solar activity cycles by using simplified MHD dynamo models and mathematical data assimilation techniques. We present recent results of this approach, including the interpretation of observational results from NASA heliophysics missions and predictive capabilities. In particular, we discuss the links between small-scale dynamo processes in the convection zone and atmospheric dynamics, as well as an early prediction of Solar Cycle 25.

Demonstration of the advanced photovoltaic solar array

NASA Technical Reports Server (NTRS)

Kurland, R. M.; Stella, P. M.

1991-01-01

The Advanced Photovoltaic Solar Array (APSA) design is reviewed. The testing results and performance estimates are summarized. The APSA design represents a critical intermediate milestone for the NASA Office of Aeronautics, Exploration, and Technology (OAET) goal of 300 W/kg at Beginning Of Life (BOL), with specific performance characteristics of 130 W/kg (BOL) and 100 W/kg at End Of Life (EOL) for a 10 year geosynchronous (GEO) 10 kW (BOL) space power system. The APSA wing design is scalable over a power range of 1 to 15 kW and is suitable for a full range of missions including Low Earth Orbit (LEO), orbital transfer from LEO to GEO and interplanetary out to 5 AU.

A solar radio dynamic spectrograph with flexible temporal-spectral resolution

NASA Astrophysics Data System (ADS)

Du, Qing-Fu; Chen, Lei; Zhao, Yue-Chang; Li, Xin; Zhou, Yan; Zhang, Jun-Rui; Yan, Fa-Bao; Feng, Shi-Wei; Li, Chuan-Yang; Chen, Yao

2017-09-01

Observation and research on solar radio emission have unique scientific values in solar and space physics and related space weather forecasting applications, since the observed spectral structures may carry important information about energetic electrons and underlying physical mechanisms. In this study, we present the design of a novel dynamic spectrograph that has been installed at the Chashan Solar Radio Observatory operated by the Laboratory for Radio Technologies, Institute of Space Sciences at Shandong University. The spectrograph is characterized by real-time storage of digitized radio intensity data in the time domain and its capability to perform off-line spectral analysis of the radio spectra. The analog signals received via antennas and amplified with a low-noise amplifier are converted into digital data at a speed reaching up to 32 k data points per millisecond. The digital data are then saved into a high-speed electronic disk for further off-line spectral analysis. Using different word lengths (1-32 k) and time cadences (5 ms-10 s) for off-line fast Fourier transform analysis, we can obtain the dynamic spectrum of a radio burst with different (user-defined) temporal (5 ms-10 s) and spectral (3 kHz˜320 kHz) resolutions. This enables great flexibility and convenience in data analysis of solar radio bursts, especially when some specific fine spectral structures are under study.

Advanced Plasmonic Materials for Dynamic Color Display.

PubMed

Shao, Lei; Zhuo, Xiaolu; Wang, Jianfang

2018-04-01

Plasmonic structures exhibit promising applications in high-resolution and durable color generation. Research on advanced hybrid plasmonic materials that allow dynamically reconfigurable color control has developed rapidly in recent years. Some of these results may give rise to practically applicable reflective displays in living colors with high performance and low power consumption. They will attract broad interest from display markets, compared with static plasmonic color printing, for example, in applications such as digital signage, full-color electronic paper, and electronic device screens. In this progress report, the most promising recent examples of utilizing advanced plasmonic materials for the realization of dynamic color display are highlighted and put into perspective. The performances, advantages, and disadvantages of different technologies are discussed, with emphasis placed on both the potential and possible limitations of various hybrid materials for dynamic plasmonic color display. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Full-size solar dynamic heat receiver thermal-vacuum tests

NASA Technical Reports Server (NTRS)

Sedgwick, L. M.; Kaufmann, K. J.; Mclallin, K. L.; Kerslake, Thomas W.

1991-01-01

The testing of a full-size, 120 kW, solar dynamic heat receiver utilizing high-temperature thermal energy storage is described. The purpose of the test program was to quantify receiver thermodynamic performance, operating temperatures, and thermal response to changes in environmental and power module interface boundary conditions. The heat receiver was tested in a vacuum chamber with liquid nitrogen cold shrouds and an aperture cold plate to partly simulate a low-Earth-orbit environment. The cavity of the receiver was heated by an infrared quartz lamp heater with 30 independently controllable zones to allow axially and circumferentially varied flux distributions. A closed-Brayton cycle engine simulator conditioned a helium-xenon gas mixture to specific interface conditions to simulate the various operational modes of the solar dynamic power module on the Space Station Freedom. Inlet gas temperature, pressure, and flow rate were independently varied. A total of 58 simulated orbital cycles, each 94 minutes in duration, was completed during the test conduct period.

Full-size solar dynamic heat receiver thermal-vacuum tests

NASA Technical Reports Server (NTRS)

Sedgwick, L. M.; Kaufmann, K. J.; Mclallin, K. L.; Kerslake, T. W.

1991-01-01

The testing of a full-size, 102 kW, solar dynamic heat receiver utilizing high-temperature thermal energy storage is described. The purpose of the test program was to quantify receiver thermodynamic performance, operating temperatures, and thermal response to changes in environmental and power module interface boundary conditions. The heat receiver was tested in a vacuum chamber with liquid nitrogen cold shrouds and an aperture cold plate to partly simulate a low-Earth-orbit environment. The cavity of the receiver was heated by an infrared quartz lamp heater with 30 independently controllable zones to allow axially and circumferentially varied flux distributions. A closed-Brayton cycle engine simulator conditioned a helium-xenon gas mixture to specific interface conditions to simulate the various operational modes of the solar dynamic power module on the Space Station Freedom. Inlet gas temperature, pressure, and flow rate were independently varied. A total of 58 simulated orbital cycles, each 94 minutes in duration, was completed during the test period.

Full-size solar dynamic heat receiver thermal-vacuum tests

NASA Astrophysics Data System (ADS)

Sedgwick, L. M.; Kaufmann, K. J.; McLallin, K. L.; Kerslake, T. W.

The testing of a full-size, 102 kW, solar dynamic heat receiver utilizing high-temperature thermal energy storage is described. The purpose of the test program was to quantify receiver thermodynamic performance, operating temperatures, and thermal response to changes in environmental and power module interface boundary conditions. The heat receiver was tested in a vacuum chamber with liquid nitrogen cold shrouds and an aperture cold plate to partly simulate a low-Earth-orbit environment. The cavity of the receiver was heated by an infrared quartz lamp heater with 30 independently controllable zones to allow axially and circumferentially varied flux distributions. A closed-Brayton cycle engine simulator conditioned a helium-xenon gas mixture to specific interface conditions to simulate the various operational modes of the solar dynamic power module on the Space Station Freedom. Inlet gas temperature, pressure, and flow rate were independently varied. A total of 58 simulated orbital cycles, each 94 minutes in duration, was completed during the test period.

Structural evaluation of concepts for a solar energy concentrator for Space Station advanced development program

NASA Technical Reports Server (NTRS)

Kenner, Winfred S.; Rhodes, Marvin D.

1994-01-01

Solar dynamic power systems have a higher thermodynamic efficiency than conventional photovoltaic systems; therefore they are attractive for long-term space missions with high electrical power demands. In an investigation conducted in support of a preliminary concept for Space Station Freedom, an approach for a solar dynamic power system was developed and a number of the components for the solar concentrator were fabricated for experimental evaluation. The concentrator consists of hexagonal panels comprised of triangular reflective facets which are supported by a truss. Structural analyses of the solar concentrator and the support truss were conducted using finite-element models. A number of potential component failure scenarios were postulated and the resulting structural performance was assessed. The solar concentrator and support truss were found to be adequate to meet a 1.0-Hz structural dynamics design requirement in pristine condition. However, for some of the simulated component failure conditions, the fundamental frequency dropped below the 1.0-Hz design requirement. As a result, two alternative concepts were developed and assessed. One concept incorporated a tetrahedral ring truss support for the hexagonal panels: the second incorporated a full tetrahedral truss support for the panels. The results indicate that significant improvements in stiffness can be obtained by attaching the panels to a tetrahedral truss, and that this concentrator and support truss will meet the 1.0-Hz design requirement with any of the simulated failure conditions.

Advanced Research Deposition System (ARDS) for processing CdTe solar cells

NASA Astrophysics Data System (ADS)

Barricklow, Keegan Corey

CdTe solar cells have been commercialized at the Gigawatt/year level. The development of volume manufacturing processes for next generation CdTe photovoltaics (PV) with higher efficiencies requires research systems with flexibility, scalability, repeatability and automation. The Advanced Research Deposition Systems (ARDS) developed by the Materials Engineering Laboratory (MEL) provides such a platform for the investigation of materials and manufacturing processes necessary to produce the next generation of CdTe PV. Limited by previous research systems, the ARDS was developed to provide process and hardware flexibility, accommodating advanced processing techniques, and capable of producing device quality films. The ARDS is a unique, in-line process tool with nine processing stations. The system was designed, built and assembled at the Materials Engineering Laboratory. Final assembly, startup, characterization and process development are the focus of this research. Many technical challenges encountered during the startup of the ARDS were addressed in this research. In this study, several hardware modifications needed for the reliable operation of the ARDS were designed, constructed and successfully incorporated into the ARDS. The effect of process condition on film properties for each process step was quantified. Process development to achieve 12% efficient baseline solar cell required investigation of discrete processing steps, troubleshooting process variation, and developing performance correlations. Subsequent to this research, many advances have been demonstrated with the ARDS. The ARDS consistently produces devices of 12% +/-.5% by the process of record (POR). The champion cell produced to date utilizing the ARDS has an efficiency of 16.2% on low cost commercial sodalime glass and utilizes advanced films. The ARDS has enabled investigation of advanced concepts for processing CdTe devices including, Plasma Cleaning, Plasma Enhanced Closed Space Sublimation

Data Distribution System (DDS) and Solar Dynamic Observatory Ground Station (SDOGS) Integration Manager

NASA Technical Reports Server (NTRS)

Pham, Kim; Bialas, Thomas

2012-01-01

The DDS SDOGS Integration Manager (DSIM) provides translation between native control and status formats for systems within DDS and SDOGS, and the ASIST (Advanced Spacecraft Integration and System Test) control environment in the SDO MOC (Solar Dynamics Observatory Mission Operations Center). This system was created in response for a need to centralize remote monitor and control of SDO Ground Station equipments using ASIST control environment in SDO MOC, and to have configurable table definition for equipment. It provides translation of status and monitoring information from the native systems into ASIST-readable format to display on pages in the MOC. The manager is lightweight, user friendly, and efficient. It allows data trending, correlation, and storing. It allows using ASIST as common interface for remote monitor and control of heterogeneous equipments. It also provides failover capability to back up machines.

Numerical research of dynamic characteristics in tower solar cavity receiver based on step-change radiation flux

NASA Astrophysics Data System (ADS)

Chen, Zhengwei; Wang, Yueshe; Hao, Yun; Wang, Qizhi

2013-07-01

The solar cavity receiver is an important light-energy to thermal-energy convector in the tower solar thermal power plant system. The heat flux in the inner surface of the cavity will show the characteristics of non-continuous step change especially in non-normal and transient weather conditions, which may result in a continuous dynamic variation of the characteristic parameters. Therefore, the research of dynamic characteristics of the receiver plays a very important role in the operation and the control safely in solar cavity receiver system. In this paper, based on the non-continuous step change of radiation flux, a non-linear dynamic model is put forward to obtain the effects of the non-continuous step change radiation flux and step change feed water flow on the receiver performance by sequential modular approach. The subject investigated in our study is a 1MW solar power station constructed in Yanqing County, Beijing. This study has obtained the dynamic responses of the characteristic parameters in the cavity receiver, such as drum pressure, drum water level, main steam flow and main steam enthalpy under step change radiation flux. And the influence law of step-change feed water flow to the dynamic characteristics in the receiver also has been analyzed. The results have a reference value for the safe operation and the control in solar cavity receiver system.

Dynamics of Coronal Structures Captured During the 2012 and 2013 Total Solar Eclipses

NASA Astrophysics Data System (ADS)

Alzate, N.; Habbal, S. R.; Druckmuller, M.

2017-12-01

White light eclipse images taken during total solar eclipses provide a very high dynamic range spanning tens of solar radii starting from the solar surface. They capture the instantaneous state of the corona, including dynamic events. We present observations of the 2012 November 13 and 2013 November 3 total solar eclipses, taken by Constantinos Emmanouilidis, in which we captured high latitude tethered prominences accompanied by CMEs, as well as several `atypical' large scale structures, spanning a few solar radii above the solar surface. By complementing the eclipse observations with co-temporaneous SDO/AIA, STEREO/EUVI and SOHO/LASCO observations, we show how the shape of the atypical structures outlines the shape of faint CME shock fronts, driven by flaring activities. The tethered prominences were imaged from their anchor at the solar surface out to several solar radii. The SDO/AIA 30.4, 17.1 and 19.3 nm emission clearly show how a direct link between the cool (104 - 105 K) filamentary emission from prominence material, and the filamentary structures emitting at coronal temperatures (> 106 K), is unmistakably present. The observed survival of these tethered systems out to the field of view of LASCO C3, establishes the likely origin of counter-streaming electrons associated with CMEs observed in interplanetary space (ICMEs). They also provide new insights for CME-initiation models associated with prominence eruptions. Our work highlights the uniqueness of eclipse observations in identifying the impact of transit events on large-scale coronal structures.

The Solar Dynamics Observatory, Studying the Sun and Its Influence on Other Bodies in the Solar System

NASA Technical Reports Server (NTRS)

Chamberlin, P. C.

2011-01-01

The solar photon output, which was once thought to be constant, varies over all time scales from seconds during solar flares to years due to the solar cycle. These solar variations cause significant deviations in the Earth and space environments on similar time scales, such as affecting the atmospheric densities and composition of particular atoms, molecules, and ions in the atmospheres of the Earth and other planets. Presented and discussed will be examples of unprecedented observations from NASA's new solar observatory, the Solar Dynamics Observatory (SDO). Using three specialized instruments, SDO measures the origins of solar activity from inside the Sun, though its atmosphere, then accurately measuring the Sun's radiative output in X-ray and EUV wavelengths (0.1-121 nm). Along with the visually appealing observations will be discussions of what these measurements can tell us about how the plasma motions in all layers of the Sun modifies and strengthens the weak solar dipole magnetic field to drive large energy releases in solar eruptions. Also presented will be examples of how the release of the Sun's energy, in the form of photons and high energy particles, physically influence other bodies in the solar system such as Earth, Mars, and the Moon, and how these changes drive changes in the technology that we are becoming dependent upon. The presentation will continuously emphasize how SDO, the first satellite in NASA's Living with a Star program, improving our understanding of the variable Sun and its Heliospheric influence.

Advances In Understanding Solar And Stellar Flares

NASA Astrophysics Data System (ADS)

Kowalski, Adam F.

2016-07-01

Flares result from the sudden reconnection and relaxation of magnetic fields in the coronae of stellar atmospheres. The highly dynamic atmospheric response produces radiation across the electromagnetic spectrum, from the radio to X-rays, on a range of timescales, from seconds to days. New high resolution data of solar flares have revealed the intrinsic spatial properties of the flaring chromosphere, which is thought to be where the majority of the flare energy is released as radiation in the optical and near-UV continua and emission lines. New data of stellar flares have revealed the detailed properties of the broadband (white-light) continuum emission, which provides straightforward constraints for models of the transformation of stored magnetic energy in the corona into thermal energy of the lower atmosphere. In this talk, we discuss the physical processes that produce several important spectral phenomena in the near-ultraviolet and optical as revealed from new radiative-hydrodynamic models of flares on the Sun and low mass stars. We present recent progress with high-flux nonthermal electron beams in reproducing the observed optical continuum color temperature of T 10,000 K and the Balmer jump properties in the near-ultraviolet. These beams produce dense, heated chromospheric condensations, which can explain the shape and strength of the continuum emission in M dwarf flares and the red-wing asymmetries in the chromospheric emission lines in recent observations of solar flares from the Interface Region Imaging Spectrograph. Current theoretical challenges and future modeling directions will be discussed, as well as observational synergies between solar and stellar flares.

Interfacial Materials for Organic Solar Cells: Recent Advances and Perspectives

PubMed Central

Yin, Zhigang; Wei, Jiajun

2016-01-01

Organic solar cells (OSCs) have shown great promise as low‐cost photovoltaic devices for solar energy conversion over the past decade. Interfacial engineering provides a powerful strategy to enhance efficiency and stability of OSCs. With the rapid advances of interface layer materials and active layer materials, power conversion efficiencies (PCEs) of both single‐junction and tandem OSCs have exceeded a landmark value of 10%. This review summarizes the latest advances in interfacial layers for single‐junction and tandem OSCs. Electron or hole transporting materials, including metal oxides, polymers/small‐molecules, metals and metal salts/complexes, carbon‐based materials, organic‐inorganic hybrids/composites, and other emerging materials, are systemically presented as cathode and anode interface layers for high performance OSCs. Meanwhile, incorporating these electron‐transporting and hole‐transporting layer materials as building blocks, a variety of interconnecting layers for conventional or inverted tandem OSCs are comprehensively discussed, along with their functions to bridge the difference between adjacent subcells. By analyzing the structure–property relationships of various interfacial materials, the important design rules for such materials towards high efficiency and stable OSCs are highlighted. Finally, we present a brief summary as well as some perspectives to help researchers understand the current challenges and opportunities in this emerging area of research. PMID:27812480

Dynamics of the penetration boundaries of solar protons during a strong magnetic storm

NASA Technical Reports Server (NTRS)

Glukhov, G. A.; Kratenko, Y. P.; Mineev, Y. V.

1985-01-01

The variations in the equatorial penetration boundary of solar protons with E sub p = 0.9 to 8.0 MeV during a strong magnetic storm of April 3 to 5, were analyzed. The dynamics of this boundary is compared with the dynamics of the outer trapping boundary of electrons with E sub e = - 0.3 to 0.6 MeV. The solar-proton penetration and the structure of the real magnetic field are studied. The unique data on the thin structure of development of a magnetospheric substorm were obtained for the first time.

NASA's Solar Dynamics Observatory Unveils New Images

NASA Image and Video Library

2010-04-20

Philip H. Scherrer (left) principal investigator, Helioseismic and Magnetic Imager instrument, Stanford University in Palo Alto, speaks during a briefing to discuss recent images from NASA's Solar Dynamics Observatory, or SDO, while colleagues Tom Woods, principal investigator, Extreme Ultraviolet Variability Experiment instrument, Laboratory for Atmospheric and Space Physics, University of Colorado in Boulder and Madhulika Guhathakurta, SDO program scientist, NASA Headquarters (right) look on Wednesday, April 21, 2010, at the Newseum in Washington. Photo Credit: (NASA/Carla Cioffi)

Advanced solar energy conversion. [solar pumped gas lasers

NASA Technical Reports Server (NTRS)

Lee, J. H.

1981-01-01

An atomic iodine laser, a candidate for the direct solar pumped lasers, was successfully excited with a 4 kW beam from a xenon arc solar simulator, thus proving the feasibility of the concept. The experimental set up and the laser output as functions of operating conditions are presented. The preliminary results of the iodine laser amplifier pumped with the HCP array to which a Q switch for giant pulse production was coupled are included. Two invention disclosures - a laser driven magnetohydrodynamic generator for conversion of laser energy to electricity and solar pumped gas lasers - are also included.

Multiple-etalon systems for the Advanced Technology Solar Telescope

NASA Technical Reports Server (NTRS)

Gary, G. Allen; Balasubramaniam, K. S.; Sigwarth, Michael

2003-01-01

Multiple etalon systems are discussed that meet the science requirements for a narrow-passband imaging system for the 4-meter National Solar Observatory (NSO)/Advance Technology Solar Telescope (ATST). A multiple etalon system can provide an imaging interferometer that works in four distinct modes: as a spectro-polarimeter, a filter-vector magnetograph, an intermediate-band imager, and broadband high-resolution imager. Specific dual and triple etalon configurations are described that provide a spectrographic passband of 2.0-3.5 micron and reduce parasitic light levels to 10(exp -4) as required for precise polarization measurement, e.g., Zeeman measurements of magnetic sensitive lines. A TESOS-like (Telecentric Etalon SOlar Spectrometer) triple etalon system provides a spectral purity of 10(exp -5). The triple designs have the advantage of reducing the finesse requirement on each etalon; allow the use of more stable blocking filters, and have very high spectral purity. A dual-etalon double-pass (Cavallini-like) system can provide a competing configuration. Such a dual-etalon design can provide high contrast. The selection of the final focal plane instrument will depend on a trade-off between an ideal instrument and practical reality. The trade study will include the number of etalons, their aperture sizes, complexities of the optical train, number of blocking filters, configuration of the electronic control system, computer interfaces, temperature controllers, etalon controllers, and their associated feedback electronics. The heritage of single and multiple etalon systems comes from their use in several observatories, including the Marshall Space Flight Center (MSFC) Solar Observatory, Sacramento Peak Observatory (NSO), and Kiepenheuer-Institut fur Sonnenphysik (KIS, Germany), Mees Solar Observatory (University of Hawaii), and Arcetri Astrophysical Observatory (Italy). The design of the ATST multiple etalon system will benefit from the experience gained at these

Multiple Etalon Systems for the Advanced Technology Solar Telescope

NASA Technical Reports Server (NTRS)

Gary, G. Allen; Balasubramaniam, K. S.; Sigwarth, Michael; Six, N. Frank (Technical Monitor)

2002-01-01

Multiple etalons systems are discussed that meet the 4-meter NSO/Advance Technology Solar Telescope (http://www.nso.edu/ATST/index.html) instrument and science requirements for a narrow bandpass imaging system. A multiple etalon system can provide an imaging interferometer working in four distinct modes: as a spectro-polarimeter, a filter-vector magnetograph, and a wide-band and broad-band high-resolution imager. Specific dual and triple etalon configurations will be described that provides spectrographic passband of 2.0-3.5nm and reduces parasitic light levels to 1/10000 as required by precise polarization measurement, e.g., Zeeman measurements of magnetic sensitive lines. A TESOS-like triple etalon system provides for spectral purity of 100 thousandths. The triple designs have the advantage of reducing the finesse requirement on each etalon, allowing much more stable blocking filters, and can have very high spectral purity. A dual-etalon double-pass Cavallini-like configuration can provide a competing configuration. This design can provide high contrast with only a double etalon. The selection of the final focal plan instrument will depend on a trade-off of the ideal instrument versus reality, the number of etalons, the aperture of etalons, the number of blocking filters the electronic control system and computer interfaces, the temperature control and controllers for the etalons and the electronics. The use of existing experience should provide significant cost savings. The heritage of use of etalons and multiple etalon systems in solar physics come from a number of observatories, which includes MSFC Solar Observatory (NASA), Sac Peak Observatory (NSO), and Kiepenheuer Institute for Solar Physics (Germany), Mees Solar Observatory (University of Hawaii), and Arcetri Astrophysical Observatory (Italy). The design of the ATST multiple etalon system will reply on the existing experience from these observatories.

Advances in solar radio astronomy

NASA Technical Reports Server (NTRS)

Kundu, M. R.

1982-01-01

The status of the observations and interpretations of the sun's radio emission covering the entire radio spectrum from millimeter wavelengths to hectometer and kilometer wavelengths is reviewed. Emphasis is given to the progress made in solar radio physics as a result of recent advances in plasma and radiation theory. It is noted that the capability now exists of observing the sun with a spatial resolution of approximately a second of arc and a temporal resolution of about a millisecond at centimeter wavelengths and of obtaining fast multifrequency two-dimensional pictures of the sun at meter and decameter wavelengths. A summary is given of the properties of nonflaring active regions at millimeter, centimeter, and meter-decameter wavelengths. The properties of centimeter wave bursts are discussed in connection with the high spatial resolution observations. The observations of the preflare build-up of an active region are reviewed. High spatial resolution observations (a few seconds of arc to approximately 1 arcsec) are discussed, with particular attention given to the one- and two-dimensional maps of centimeter-wavelength burst sources.

FFT analysis of sensible-heat solar-dynamic receivers

NASA Astrophysics Data System (ADS)

Lund, Kurt O.

The use of solar dynamic receivers with sensible energy storage in single-phase materials is considered. The feasibility of single-phase designs with weight and thermal performance comparable to existing two-phase designs is addressed. Linearized heat transfer equations are formulated for the receiver heat storage, representing the periodic input solar flux as the sum of steady and oscillating distributions. The steady component is solved analytically to produce the desired receiver steady outlet gas temperature, and the FFT algorithm is applied to the oscillating components to obtain the amplitudes and mode shapes of the oscillating solid and gas temperatures. The results indicate that sensible-heat receiver designs with performance comparable to state-of-the-art two-phase receivers are available.

Heliophysics at total solar eclipses

NASA Astrophysics Data System (ADS)

Pasachoff, Jay M.

2017-08-01

Observations during total solar eclipses have revealed many secrets about the solar corona, from its discovery in the 17th century to the measurement of its million-kelvin temperature in the 19th and 20th centuries, to details about its dynamics and its role in the solar-activity cycle in the 21st century. Today's heliophysicists benefit from continued instrumental and theoretical advances, but a solar eclipse still provides a unique occasion to study coronal science. In fact, the region of the corona best observed from the ground at total solar eclipses is not available for view from any space coronagraphs. In addition, eclipse views boast of much higher quality than those obtained with ground-based coronagraphs. On 21 August 2017, the first total solar eclipse visible solely from what is now United States territory since long before George Washington's presidency will occur. This event, which will cross coast-to-coast for the first time in 99 years, will provide an opportunity not only for massive expeditions with state-of-the-art ground-based equipment, but also for observations from aloft in aeroplanes and balloons. This set of eclipse observations will again complement space observations, this time near the minimum of the solar activity cycle. This review explores the past decade of solar eclipse studies, including advances in our understanding of the corona and its coronal mass ejections as well as terrestrial effects. We also discuss some additional bonus effects of eclipse observations, such as recreating the original verification of the general theory of relativity.

Initial results from the Solar Dynamic (SD) Ground Test Demonstration (GTD) project at NASA Lewis

NASA Technical Reports Server (NTRS)

Shaltens, Richard K.; Boyle, Robert V.

1995-01-01

A government/industry team designed, built, and tested a 2 kWe solar dynamic space power system in a large thermal/vacuum facility with a simulated sun at the NASA Lewis Research Center. The Lewis facility provides an accurate simulation of temperatures, high vacuum, and solar flux as encountered in low earth orbit. This paper reviews the goals and status of the Solar Dynamic (SD) Ground Test Demonstration (GTD) program and describes the initial testing, including both operational and performance data. This SD technology has the potential as a future power source for the International Space Station Alpha.

NASA's SDO Sees Solar Flares

NASA Image and Video Library

2014-06-10

A solar flare bursts off the left limb of the sun in this image captured by NASA's Solar Dynamics Observatory on June 10, 2014, at 7:41 a.m. EDT. This is classified as an X2.2 flare, shown in a blend of two wavelengths of light: 171 and 131 angstroms, colorized in gold and red, respectively. Credit: NASA/SDO/Goddard/Wiessinger NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Laboratory study supporting the interpretation of Solar Dynamics Observatory data

DOE PAGES

Trabert, E.; Beiersdorfer, P.

2015-01-29

High-resolution extreme ultraviolet spectra of ions in an electron beam ion trap are investigated as a laboratory complement of the moderate-resolution observation bands of the AIA experiment on board the Solar Dynamics Observatory (SDO) spacecraft. Here, the latter observations depend on dominant iron lines of various charge states which in combination yield temperature information on the solar plasma. Our measurements suggest additions to the spectral models that are used in the SDO data interpretation. In the process, we also note a fair number of inconsistencies among the wavelength reference data bases.

Recent developments for realistic solar models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Serenelli, Aldo M.

2014-05-02

The 'solar abundance problem' has triggered a renewed interest in revising the concept of SSM from different perspectives: 1) constituent microphysics: equation of state, nuclear rates, radiative opacities; 2) constituent macrophysics: the physical processes impact the evolution of the Sun and its present-day structure, e.g. dynamical processes induced by rotation, presence of magnetic fields; 3) challenge the hypothesis that the young Sun was chemically homogeneous: the possible interaction of the young Sun with its protoplanetary disk. Here, I briefly review and then present a (personal) view on recent advances and developments on solar modeling, part of them carried out asmore » attempts to solve the solar abundance problem.« less

Structure and Dynamics of the Quiet Solar Chromosphere

NASA Technical Reports Server (NTRS)

Kalkofen, Wolfgang; Wagner, William (Technical Monitor)

2003-01-01

For the meeting of the AAS/SPD in Albuquerque, NM, I organized a Topical Session of the AAS on Structure and Dynamics of Chromospheres. The grant support was used to bring to the US two of the speakers from abroad. I had invited them for presentations at the Session: Dr. Klaus Wilhelm, the former PI of the SUMER instrument on SOHO, from the Max-Planck Institut in Lindau, Germany, and Dr. Sirajul Hasan, from the Indian Institute of Astrophysics in Bangalore, India. Both speakers preceded their trip to the AAS meeting with a stay at the Smithsonian Astrophysical Observatory, where they interacted with members of the Solar and Stellar Physics division. The highlights of the visits were the talks at the AAS/SPD meeting, in which six invited speakers told the audience of astronomers about current problems in solar physics and their relation to stellar problems. An important result of the visits is a paper by Dr. Wilhelm and me on 'Observations of the upper solar chromosphere with SUMER on SOHO', which has been submitted to Astronomy and Astrophysics for publication.

Solar Impulse's Solar-Powered Plane

ScienceCinema

Moniz, Ernest; Piccard, Bertrand; Reicher, Dan

2018-01-16

Solar Impulse lands in Washington, DC at Washington Dulles International Airport as part of its journey across the United States. Secretary Ernest Moniz speaks about how advancements like those at the Department of Energy are leading the way for innovations like the solar-powered plane. Footage of the solar-powered plane courtesy of Solar Impulse.

Solar Impulse's Solar-Powered Plane

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moniz, Ernest; Piccard, Bertrand; Reicher, Dan

Solar Impulse lands in Washington, DC at Washington Dulles International Airport as part of its journey across the United States. Secretary Ernest Moniz speaks about how advancements like those at the Department of Energy are leading the way for innovations like the solar-powered plane. Footage of the solar-powered plane courtesy of Solar Impulse.

Lunar Solar Origins Exploration (LunaSOX)

NASA Technical Reports Server (NTRS)

Cooper, John F.; King, Joseph H.; Papitashvili, Natasha; Lipatov, Alexander S.; Sittler, Edward C.; Hartle, Richard E.

2011-01-01

The Moon offers a unique vantage point from which to investigate the Sun and its interaction via the solar wind magnetic fields, plasma, and energetic particles with the geospace system including the Moon itself. The lunar surface and exosphere provide in part a record of solar coronal plasma material input and resultant space weathering over billions of years. The structure and dynamics of solar wind interactions with the Moon provide an accessible near-Earth laboratory environment for study of general solar wind interactions with the vast multitude of airless asteroidal bodies of the inner solar system. Spacecraft in lunar orbit have the often simultaneous opportunity, except when in the Earth's magnetosphere, to make in-situ compositional measurements of the solar wind plasma and to carry out remote observations from the Moon of the solar corona, potentially enabled by lunar limb occultation of the solar disk. The LunaSOX project at NASA Goddard Space Flight Center is addressing these heliophysical science objectives from and of the Moon with support from NASA's Lunar Advanced Science and Exploration Research (LASER) program: (1) specify history of solar wind parameters at and sunward of the Moon through enhanced access (http://lunasox.gsfc.nasa.gov/) to legacy and operational mission data products from the Apollo era to the present, (2) model field and plasma interactions with the lunar surface, exosphere, and wake, as constrained by the available data, through hybrid kinetic code simulations, and (3) advance mission concepts for heliophysics from and of the Moon.

Considerations of solar wind dynamics in mapping of Jupiter's auroral features to magnetospheric sources

NASA Astrophysics Data System (ADS)

Gyalay, S.; Vogt, M.; Withers, P.

2015-12-01

Previous studies have mapped locations from the magnetic equator to the ionosphere in order to understand how auroral features relate to magnetospheric sources. Vogt et al. (2011) in particular mapped equatorial regions to the ionosphere by using a method of flux equivalence—requiring that the magnetic flux in a specified region at the equator is equal to the magnetic flux in the region to which it maps in the ionosphere. This is preferred to methods relying on tracing field lines from global Jovian magnetic field models, which are inaccurate beyond 30 Jupiter radii from the planet. That previous study produced a two-dimensional model—accounting for changes with radial distance and local time—of the normal component of the magnetic field in the equatorial region. However, this two-dimensional fit—which aggregated all equatorial data from Pioneer 10, Pioneer 11, Voyager 1, Voyager 2, Ulysses, and Galileo—did not account for temporal variability resulting from changing solar wind conditions. Building off of that project, this study aims to map the Jovian aurora to the magnetosphere for two separate cases: with a nominal magnetosphere, and with a magnetosphere compressed by high solar wind dynamic pressure. Using the Michigan Solar Wind Model (mSWiM) to predict the solar wind conditions upstream of Jupiter, intervals of high solar wind dynamic pressure were separated from intervals of low solar wind dynamic pressure—thus creating two datasets of magnetometer measurements to be used for two separate 2D fits, and two separate mappings.

Performance of High-Efficiency Advanced Triple-Junction Solar Panels for the LILT Mission Dawn

NASA Technical Reports Server (NTRS)

Fatemi, Navid S.; Sharma, Surya; Buitrago, Oscar; Sharps, Paul R.; Blok, Ron; Kroon, Martin; Jalink, Cees; Harris, Robin; Stella, Paul; Distefano, Sal

2005-01-01

NASA's Discovery Mission Dawn is designed to (LILT) conditions. operate within the solar system's Asteroid belt, where the large distance from the sun creates a low-intensity, low-temperature (LILT) condition. To meet the mission power requirements under LlLT conditions, very high-efficiency multi-junction solar cells were selected to power the spacecraft to be built by Orbital Sciences Corporation (OSC) under contract with JPL. Emcore's InGaP/InGaAs/Ge advanced triple-junction (ATJ) solar cells, exhibiting an average air mass zero (AMO) efficiency of greater than 27.6% (one-sun, 28 C), were used to populate the solar panels [1]. The two solar array wings, to be built by Dutch Space, with 5 large- area panels each (total area of 36.4 sq. meters) are projected to produce between 10.3 kWe and 1.3 kWe of end-of life (EOL) power in the 1.0 to 3.0 AU range, respectively. The details of the solar panel design, testing and power analysis are presented.

Nanostructured Solar Cells.

PubMed

Chen, Guanying; Ning, Zhijun; Ågren, Hans

2016-08-09

We are glad to announce the Special Issue "Nanostructured Solar Cells", published in Nanomaterials. This issue consists of eight articles, two communications, and one review paper, covering major important aspects of nanostructured solar cells of varying types. From fundamental physicochemical investigations to technological advances, and from single junction solar cells (silicon solar cell, dye sensitized solar cell, quantum dots sensitized solar cell, and small molecule organic solar cell) to tandem multi-junction solar cells, all aspects are included and discussed in this issue to advance the use of nanotechnology to improve the performance of solar cells with reduced fabrication costs.

Advanced Nanomaterials for High-Efficiency Solar Cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Junhong

2013-11-29

Energy supply has arguably become one of the most important problems facing humankind. The exponential demand for energy is evidenced by dwindling fossil fuel supplies and record-high oil and gas prices due to global population growth and economic development. This energy shortage has significant implications to the future of our society, in addition to the greenhouse gas emission burden due to consumption of fossil fuels. Solar energy seems to be the most viable choice to meet our clean energy demand given its large scale and clean/renewable nature. However, existing methods to convert sun light into electricity are not efficient enoughmore » to become a practical alternative to fossil fuels. This DOE project aims to develop advanced hybrid nanomaterials consisting of semiconductor nanoparticles (quantum dots or QDs) supported on graphene for cost-effective solar cells with improved conversion efficiency for harvesting abundant, renewable, clean solar energy to relieve our global energy challenge. Expected outcomes of the project include new methods for low-cost manufacturing of hybrid nanostructures, systematic understanding of their properties that can be tailored for desired applications, and novel photovoltaic cells. Through this project, we have successfully synthesized a number of novel nanomaterials, including vertically-oriented graphene (VG) sheets, three-dimensional (3D) carbon nanostructures comprising few-layer graphene (FLG) sheets inherently connected with CNTs through sp{sup 2} carbons, crumpled graphene (CG)-nanocrystal hybrids, CdSe nanoparticles (NPs), CdS NPs, nanohybrids of metal nitride decorated on nitrogen-doped graphene (NG), QD-carbon nanotube (CNT) and QD-VG-CNT structures, TiO{sub 2}-CdS NPs, and reduced graphene oxide (RGO)-SnO{sub 2} NPs. We further assembled CdSe NPs onto graphene sheets and investigated physical and electronic interactions between CdSe NPs and the graphene. Finally we have demonstrated various applications of these

Use of solar advanced oxidation processes for wastewater treatment: Follow-up on degradation products, acute toxicity, genotoxicity and estrogenicity.

PubMed

Brienza, M; Mahdi Ahmed, M; Escande, A; Plantard, G; Scrano, L; Chiron, S; Bufo, S A; Goetz, V

2016-04-01

Wastewater tertiary treatment by advanced oxidation processes is thought to produce a treated effluent with lower toxicity than the initial influent. Here we performed tertiary treatment of a secondary effluent collected from a Waste Water Treatment Plant via homogeneous (solar/HSO5(-)/Fe(2+)) and heterogeneous (solar/TiO2) solar advanced oxidation aiming at the assessment of their effectiveness in terms of contaminants' and toxicity abatement in a plain solar reactor. A total of 53 organic contaminants were qualitatively identified by liquid chromatography coupled to high-resolution mass spectrometry after solid phase extraction. Solar advanced oxidation totally or partially removed the major part of contaminants detected within 4.5 h. Standard toxicity tests were performed using Vibrio fischeri, Daphnia magna, Pseudokirchneriella subcapitata and Brachionus calyciflorus organisms to evaluate acute and chronic toxicity in the secondary or tertiary effluents, and the EC50% was calculated. Estrogenic and genotoxic tests were carried out in an attempt to obtain an even sharper evaluation of potential hazardous effects due to micropollutants or their degradation by-products in wastewater. Genotoxic effects were not detected in effluent before or after treatment. However, we observed relevant estrogenic activity due to the high sensitivity of the HELN ERα cell line. Copyright © 2016 Elsevier Ltd. All rights reserved.

Advances in photographic X-ray imaging for solar astronomy

NASA Technical Reports Server (NTRS)

Moses, J. Daniel; Schueller, R.; Waljeski, K.; Davis, John M.

1989-01-01

The technique of obtaining quantitative data from high resolution soft X-ray photographic images produced by grazing incidence optics was successfully developed to a high degree during the Solar Research Sounding Rocket Program and the S-054 X-Ray Spectrographic Telescope Experiment Program on Skylab. Continued use of soft X-ray photographic imaging in sounding rocket flights of the High Resolution Solar Soft X-Ray Imaging Payload has provided opportunities to further develop these techniques. The developments discussed include: (1) The calibration and use of an inexpensive, commercially available microprocessor controlled drum type film processor for photometric film development; (2) The use of Kodak Technical Pan 2415 film and Kodak SO-253 High Speed Holographic film for improved resolution; and (3) The application of a technique described by Cook, Ewing, and Sutton for determining the film characteristics curves from density histograms of the flight film. Although the superior sensitivity, noise level, and linearity of microchannel plate and CCD detectors attracts the development efforts of many groups working in soft X-ray imaging, the high spatial resolution and dynamic range as well as the reliability and ease of application of photographic media assures the continued use of these techniques in solar X-ray astronomy observations.

Metallic phase-change materials for solar dynamic energy storage systems

NASA Astrophysics Data System (ADS)

Lauf, R. J.; Hamby, C., Jr.

1990-12-01

Solar (thermal) dynamic power systems for satellites require a heat storage system that is capable of operating the engine during eclipse. The conventional approach to this thermal storage problem is to use the latent heat of fluoride salts, which would melt during insolation and freeze during eclipse. Although candidate fluorides have large heats of fusion per unit mass, their poor thermal conductivity limits the rate at which energy can be transferred to and from the storage device. System performance is further limited by the high parasitic mass of the superalloy canisters needed to contain the salt. A new thermal storage system is described in which the phase-change material (PCM) is a metal (typically germanium) contained in modular graphite canisters. These modules exhibit good thermal conductivity and low parasitic mass, and they are physically and chemically stable. Prototype modules have survived over 600 melt/freeze cycles without degradation. Advanced concepts to further improve performance are described. These concepts include the selection of ternary eutectic alloys to provide a wider range of useful melting temperatures and the use of infiltration to control the location of liquid alloy and to compensate for differences in thermal expansion.

Integrated dynamic analysis simulation of space stations with controllable solar array

NASA Technical Reports Server (NTRS)

Heinrichs, J. A.; Fee, J. J.

1972-01-01

A methodology is formulated and presented for the integrated structural dynamic analysis of space stations with controllable solar arrays and non-controllable appendages. The structural system flexibility characteristics are considered in the dynamic analysis by a synthesis technique whereby free-free space station modal coordinates and cantilever appendage coordinates are inertially coupled. A digital simulation of this analysis method is described and verified by comparison of interaction load solutions with other methods of solution. Motion equations are simulated for both the zero gravity and artificial gravity (spinning) orbital conditions. Closed loop controlling dynamics for both orientation control of the arrays and attitude control of the space station are provided in the simulation by various generic types of controlling systems. The capability of the simulation as a design tool is demonstrated by utilizing typical space station and solar array structural representations and a specific structural perturbing force. Response and interaction load solutions are presented for this structural configuration and indicate the importance of using an integrated type analysis for the predictions of structural interactions.

Techno-economic projections for advanced small solar thermal electric power plants to years 1990-2000

NASA Technical Reports Server (NTRS)

Fujita, T.; Manvi, R.; Roschke, E. J.; El-Gabalawi, N.; Herrera, G.; Kuo, T. J.; Chen, K. H.

1979-01-01

Advanced technologies applicable to solar thermal electric power systems in the 1990-200 time-frame are delineated for power applications that fulfill a wide spectrum of small power needs with primary emphasis on power ratings less than 10MWe. Projections of power system characteristics (energy and capital costs as a function of capacity factor) are made based on development of identified promising technologies and are used as the basis for comparing technology development options and combinations of these options to determine developmental directions offering potential for significant improvements. Stirling engines, Brayton/Rankine combined cycles and storage/transport concepts encompassing liquid metals, and reversible-reaction chemical systems are considered for two-axis tracking systems such as the central receiver or power tower concept and distributed parabolic dish receivers which can provide efficient low-cost solar energy collection while achieving high temperatures for efficient energy conversion. Pursuit of advanced technology across a broad front can result in post-1985 solar thermal systems having the potential of approaching the goal of competitiveness with conventional power systems.

Effects of solar activity in the middle atmosphere dynamical regime over Eastern Siberia, USSR

NASA Technical Reports Server (NTRS)

Gaidukov, V. A.; Kazimirovsky, E. S.; Zhovty, E. I.; Chernigovskaya, M. A.

1989-01-01

Lower thermospheric (90 to 120 km) wind data was acquired by ground based spaced-receiver method (HF, LF) near Irkutsk (52 deg N, 104 deg E). There is interrelated solar and meteorological control of lower thermosphere dynamics. Some features of solar control effects on the wind parameters are discussed.

Advanced Deployable Shell-Based Composite Booms for Small Satellite Structural Applications Including Solar Sails

NASA Technical Reports Server (NTRS)

Fernandez, Juan M.

2017-01-01

State of the art deployable structures are mainly being designed for medium to large size satellites. The lack of reliable deployable structural systems for low cost, small volume, rideshare-class spacecraft severely constrains the potential for using small satellite platforms for affordable deep space science and exploration precursor missions that could be realized with solar sails. There is thus a need for reliable, lightweight, high packaging efficiency deployable booms that can serve as the supporting structure for a wide range of small satellite systems including solar sails for propulsion. The National Air and Space Administration (NASA) is currently investing in the development of a new class of advanced deployable shell-based composite booms to support future deep space small satellite missions using solar sails. The concepts are being designed to: meet the unique requirements of small satellites, maximize ground testability, permit the use of low-cost manufacturing processes that will benefit scalability, be scalable for use as elements of hierarchical structures (e.g. trusses), allow long duration storage, have high deployment reliability, and have controlled deployment behavior and predictable deployed dynamics. This paper will present the various rollable boom concepts that are being developed for 5-20 m class size deployable structures that include solar sails with the so-called High Strain Composites (HSC) materials. The deployable composite booms to be presented are being developed to expand the portfolio of available rollable booms for small satellites and maximize their length for a given packaged volume. Given that solar sails are a great example of volume and mass optimization, the booms were designed to comply with nominal solar sail system requirements for 6U CubeSats, which are a good compromise between those of smaller form factors (1U, 2U and 3U CubeSats) and larger ones (12 U and 27 U future CubeSats, and ESPA-class microsatellites). Solar

MHD Simulation for Investigating the Dynamic State Transition Responsible for a Solar Eruption in Active Region 12158

NASA Astrophysics Data System (ADS)

Lee, Hwanhee; Magara, Tetsuya

2018-06-01

We present a magnetohydrodynamic model of solar eruption based on the dynamic state transition from the quasi-static state to the eruptive state of an active region (AR) magnetic field. For the quasi-static state before an eruption, we consider the existence of a slow solar wind originating from an AR, which may continuously make the AR magnetic field deviate from mechanical equilibrium. In this model, we perform a three-dimensional magnetohydrodynamic simulation of AR 12158 producing a coronal mass ejection, where the initial magnetic structure of the simulation is given by a nonlinear force-free field derived from an observed photospheric vector magnetic field. We then apply a pressure-driven outflow to the upper part of the magnetic structure to achieve a quasi-static pre-eruptive state. The simulation shows that the eruptive process observed in this AR may be caused by the dynamic state transition of an AR magnetic field, which is essentially different from the destabilization of a static magnetic field. The dynamic state transition is determined from the shape evolution of the magnetic field line according to the κH-mechanism. This work demonstrates how the mechanism works to produce a solar eruption in the dynamic solar corona governed by the gravitational field and the continuous outflows of solar wind.

Global-scale equatorial Rossby waves as an essential component of solar internal dynamics

NASA Astrophysics Data System (ADS)

Löptien, Björn; Gizon, Laurent; Birch, Aaron C.; Schou, Jesper; Proxauf, Bastian; Duvall, Thomas L.; Bogart, Richard S.; Christensen, Ulrich R.

2018-05-01

The Sun’s complex dynamics is controlled by buoyancy and rotation in the convection zone. Large-scale flows are dominated by vortical motions1 and appear to be weaker than expected in the solar interior2. One possibility is that waves of vorticity due to the Coriolis force, known as Rossby waves3 or r modes4, remove energy from convection at the largest scales5. However, the presence of these waves in the Sun is still debated. Here, we unambiguously discover and characterize retrograde-propagating vorticity waves in the shallow subsurface layers of the Sun at azimuthal wavenumbers below 15, with the dispersion relation of textbook sectoral Rossby waves. The waves have lifetimes of several months, well-defined mode frequencies below twice the solar rotational frequency, and eigenfunctions of vorticity that peak at the equator. Rossby waves have nearly as much vorticity as the convection at the same scales, thus they are an essential component of solar dynamics. We observe a transition from turbulence-like to wave-like dynamics around the Rhines scale6 of angular wavenumber of approximately 20. This transition might provide an explanation for the puzzling deficit of kinetic energy at the largest spatial scales.

MAGNETOHYDRODYNAMIC SIMULATION OF THE X2.2 SOLAR FLARE ON 2011 FEBRUARY 15. II. DYNAMICS CONNECTING THE SOLAR FLARE AND THE CORONAL MASS EJECTION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Inoue, S.; Magara, T.; Choe, G. S.

2015-04-20

We clarify a relationship between the dynamics of a solar flare and a growing coronal mass ejection (CME) by investigating the dynamics of magnetic fields during the X2.2-class flare taking place in the solar active region 11158 on 2011 February 15, based on simulation results obtained from Inoue et al. We found that the strongly twisted lines formed through tether-cutting reconnection in the twisted lines of a nonlinear force-free field can break the force balance within the magnetic field, resulting in their launch from the solar surface. We further discover that a large-scale flux tube is formed during the eruptionmore » as a result of the tether-cutting reconnection between the eruptive strongly twisted lines and these ambient weakly twisted lines. The newly formed large flux tube exceeds the critical height of the torus instability. Tether-cutting reconnection thus plays an important role in the triggering of a CME. Furthermore, we found that the tangential fields at the solar surface illustrate different phases in the formation of the flux tube and its ascending phase over the threshold of the torus instability. We will discuss these dynamics in detail.« less

Dynamic tuning of optical absorbers for accelerated solar-thermal energy storage.

PubMed

Wang, Zhongyong; Tong, Zhen; Ye, Qinxian; Hu, Hang; Nie, Xiao; Yan, Chen; Shang, Wen; Song, Chengyi; Wu, Jianbo; Wang, Jun; Bao, Hua; Tao, Peng; Deng, Tao

2017-11-14

Currently, solar-thermal energy storage within phase-change materials relies on adding high thermal-conductivity fillers to improve the thermal-diffusion-based charging rate, which often leads to limited enhancement of charging speed and sacrificed energy storage capacity. Here we report the exploration of a magnetically enhanced photon-transport-based charging approach, which enables the dynamic tuning of the distribution of optical absorbers dispersed within phase-change materials, to simultaneously achieve fast charging rates, large phase-change enthalpy, and high solar-thermal energy conversion efficiency. Compared with conventional thermal charging, the optical charging strategy improves the charging rate by more than 270% and triples the amount of overall stored thermal energy. This superior performance results from the distinct step-by-step photon-transport charging mechanism and the increased latent heat storage through magnetic manipulation of the dynamic distribution of optical absorbers.

The Structure and Dynamics of the Solar Corona and Inner Heliosphere

NASA Technical Reports Server (NTRS)

Mikic, Zoran; Grebowsky, J. (Technical Monitor)

2002-01-01

This report covers technical progress during the fourth quarter of the second year of NASA Sun-Earth Connections Theory Program (SECTP) contract "The Structure and Dynamics of the Solar Corona and Inner Heliosphere," NAS5-99188, between NASA and Science Applications International Corporation (SAIC), and covers the period May 16, 2001 to August 15, 2001. Under this contract SAIC and the University of California, Irvine (UCI) have conducted research into theoretical modeling of active regions, the solar corona, and the inner heliosphere, using the MHD (magnetohydrodynamic) model.

Solar Cell and Array Technology Development for NASA Solar Electric Propulsion Missions

NASA Technical Reports Server (NTRS)

Piszczor, Michael; McNatt, Jeremiah; Mercer, Carolyn; Kerslake, Tom; Pappa, Richard

2012-01-01

NASA is currently developing advanced solar cell and solar array technologies to support future exploration activities. These advanced photovoltaic technology development efforts are needed to enable very large (multi-hundred kilowatt) power systems that must be compatible with solar electric propulsion (SEP) missions. The technology being developed must address a wide variety of requirements and cover the necessary advances in solar cell, blanket integration, and large solar array structures that are needed for this class of missions. Th is paper will summarize NASA's plans for high power SEP missions, initi al mission studies and power system requirements, plans for advanced photovoltaic technology development, and the status of specific cell and array technology development and testing that have already been conducted.

The dynamic relation between activities in the Northern and Southern solar hemispheres

NASA Astrophysics Data System (ADS)

Volobuev, D. M.; Makarenko, N. G.

2016-12-01

The north-south (N/S) asymmetry of solar activity is the most pronounced phenomenon during 11-year cycle minimums. The goal of this work is to try to interpret the asymmetry as a result of the generalized synchronization of two dynamic systems. It is assumed that these systems are localized in two solar hemispheres. The evolution of these systems is considered in the topological embeddings of a sunspot area time series obtained with the use of the Takens algorithm. We determine the coupling measure and estimate it on the time series of daily sunspot areas. The measurement made it possible to interpret the asymmetry as an exchangeable dynamic equation, in which the roles of the driver-slave components change in time for two hemispheres.

The SOLAR-C Mission: Science Objectives and Current Status

NASA Astrophysics Data System (ADS)

Suematsu, Y.; Solar-C Working Group

2016-04-01

The SOLAR-C is a Japan-led international solar mission for mid-2020s designed to investigate the magnetic activities of the Sun, focusing on the study in heating and dynamical phenomena of the chromosphere and corona, and to advance algorithms for predicting short and long term solar magnetic activities. For these purposes, SOLAR-C will carry three dedicated instruments; the Solar UV-Vis-IR Telescope (SUVIT), the EUV Spectroscopic Telescope (EUVST) and the High Resolution Coronal Imager (HCI), to jointly observe the entire visible solar atmosphere with essentially the same high spatial resolution (0.1"-0.3"), performing high resolution spectroscopic measurements over all atmospheric regions and spectro-polarimetric measurements from the photosphere through the upper chromosphere. SOLAR-C will also contribute to understand the solar influence on the Sun-Earth environments with synergetic wide-field observations from ground-based and other space missions.

Advances and recent trends in heterogeneous photo(electro)-catalysis for solar fuels and chemicals.

PubMed

Highfield, James

2015-04-15

In the context of a future renewable energy system based on hydrogen storage as energy-dense liquid alcohols co-synthesized from recycled CO2, this article reviews advances in photocatalysis and photoelectrocatalysis that exploit solar (photonic) primary energy in relevant endergonic processes, viz., H2 generation by water splitting, bio-oxygenate photoreforming, and artificial photosynthesis (CO2 reduction). Attainment of the efficiency (>10%) mandated for viable techno-economics (USD 2.00-4.00 per kg H2) and implementation on a global scale hinges on the development of photo(electro)catalysts and co-catalysts composed of earth-abundant elements offering visible-light-driven charge separation and surface redox chemistry in high quantum yield, while retaining the chemical and photo-stability typical of titanium dioxide, a ubiquitous oxide semiconductor and performance "benchmark". The dye-sensitized TiO2 solar cell and multi-junction Si are key "voltage-biasing" components in hybrid photovoltaic/photoelectrochemical (PV/PEC) devices that currently lead the field in performance. Prospects and limitations of visible-absorbing particulates, e.g., nanotextured crystalline α-Fe2O3, g-C3N4, and TiO2 sensitized by C/N-based dopants, multilayer composites, and plasmonic metals, are also considered. An interesting trend in water splitting is towards hydrogen peroxide as a solar fuel and value-added green reagent. Fundamental and technical hurdles impeding the advance towards pre-commercial solar fuels demonstration units are considered.

Long-term influence of asteroids on planet longitudes and chaotic dynamics of the solar system

NASA Astrophysics Data System (ADS)

Woillez, E.; Bouchet, F.

2017-11-01

Over timescales much longer than an orbital period, the solar system exhibits large-scale chaotic behavior and can thus be viewed as a stochastic dynamical system. The aim of the present paper is to compare different sources of stochasticity in the solar system. More precisely we studied the importance of the long term influence of asteroids on the chaotic dynamics of the solar system. We show that the effects of asteroids on planets is similar to a white noise process, when those effects are considered on a timescale much larger than the correlation time τϕ ≃ 104 yr of asteroid trajectories. We computed the timescale τe after which the effects of the stochastic evolution of the asteroids lead to a loss of information for the initial conditions of the perturbed Laplace-Lagrange secular dynamics. The order of magnitude of this timescale is precisely determined by theoretical argument, and we find that τe ≃ 104 Myr. Although comparable to the full main-sequence lifetime of the sun, this timescale is considerably longer than the Lyapunov time τI ≃ 10 Myr of the solar system without asteroids. This shows that the external sources of chaos arise as a small perturbation in the stochastic secular behavior of the solar system, rather due to intrinsic chaos.

Magnetic helicity and flux tube dynamics in the solar convection zone: Comparisons between observation and theory

NASA Astrophysics Data System (ADS)

Nandy, Dibyendu

2006-12-01

Magnetic helicity, a conserved topological parameter in ideal MHD systems, conditions close to which are realized in the solar plasma, is intimately connected to the creation and subsequent dynamics of magnetic flux tubes in the solar interior. It can therefore be used as a tool to probe such dynamics. In this paper we show how photospheric observations of magnetic helicity of isolated magnetic flux tubes, manifested as the twist and writhe of solar active regions, can constrain the creation and dynamics of flux tubes in the solar convection zone and the nature of convective turbulence itself. We analyze the observed latitudinal distribution of twists in photospheric active regions, derived from solar vector magnetograms, in the largest such sample studied till-date. We confirm and put additional constraints on the hemispheric twist helicity trend and find that the dispersion in the active region twist distribution is latitude-independent, implying that the amplitude of turbulent fluctuations does not vary with latitude in the convection zone. Our data set also shows that the amplitude and dispersion of twist decreases with increasing magnetic size of active regions, supporting the conclusion that larger flux tubes are less affected by turbulence. Among the various theoretical models that have been proposed till-date to explain the origin of twist, our observations best match the Σ effect model, which invokes helical turbulent buffeting of rising flux tubes as the mechanism for twist creation. Finally, we complement our analysis of twists with past observations of tilts in solar active regions and tie them in with theoretical modeling studies, to build up a comprehensive picture of the dynamics of twisted magnetic flux tubes throughout the solar convection zone. This general framework, binding together theory and observations, suggests that flux tubes have a wide range of twists in the solar convection zone, with some as high as to make them susceptible to the

The SOLAR-C Mission

NASA Astrophysics Data System (ADS)

Suematsu, Y.

2015-12-01

The Solar-C is a Japan-led international solar mission planned to be launched in mid2020. It is designed to investigate the magnetic activities of the Sun, focusing on the study in heating and dynamical phenomena of the chromosphere and corona, and also to develop an algorithm for predicting short and long term solar evolution. Since it has been revealed that the different parts of the magnetized solar atmosphere are essentially coupled, the SOLAR-C should tackle the spatial scales and temperature regimes that need to be observed in order to achieve a comprehensive physical understanding of this coupling. The science of Solar-C will greatly advance our understanding of the Sun, of basic physical processes operating throughout the universe. To dramatically improve the situation, SOLAR-C will carry three dedicated instruments; the Solar UV-Vis-IR Telescope (SUVIT), the EUV Spectroscopic Telescope (EUVST) and the High Resolution Coronal Imager (HCI), to jointly observe the entire visible solar atmosphere with essentially the same high spatial resolution (0.1-0.3 arcsec), performing high resolution spectroscopic measurements over all atmospheric regions and spectro-polarimetric measurements from the photosphere through the upper chromosphere. In addition, Solar-C will contribute to our understanding on the influence of the Sun-Earth environments with synergetic wide-field observations from ground-based and other space missions. Some leading science objectives and the mission concept, including designs of the three instruments aboard SOLAR-C will be presented.

Advances in graphene-based semiconductor photocatalysts for solar energy conversion: fundamentals and materials engineering.

PubMed

Xie, Xiuqiang; Kretschmer, Katja; Wang, Guoxiu

2015-08-28

Graphene-based semiconductor photocatalysis has been regarded as a promising technology for solar energy storage and conversion. In this review, we summarized recent developments of graphene-based photocatalysts, including preparation of graphene-based photocatalysts, typical key advances in the understanding of graphene functions for photocatalytic activity enhancement and methodologies to regulate the electron transfer efficiency in graphene-based composite photocatalysts, by which we hope to offer enriched information to harvest the utmost fascinating properties of graphene as a platform to construct efficient graphene-based composite photocatalysts for solar-to-energy conversion.

Using Advanced Computing in Applied Dynamics: From the Dynamics of Granular Material to the Motion of the Mars Rover

DTIC Science & Technology

2013-08-26

USING ADVANCED COMPUTING IN APPLIED DYNAMICS : FROM THE DYNAMICS OF GRANULAR MATERIAL TO THE MOTION OF THE MARS ROVER Dan Negrut NVIDIA CUDA...USING ADVANCED COMPUTING IN APPLIED DYNAMICS : FROM THE DYNAMICS OF GRANULAR MATERIAL TO THE MOTION OF THE MARS ROVER 5a. CONTRACT NUMBER W911NF-11-F...University of Parma, Italy • Drs. Paramsothy Jayakumar & David Lamb, US Army TARDEC • Mihai Anitescu, University of Chicago & Argonne National Lab

The effects of regional insolation differences upon advanced solar thermal electric power plant performance and energy costs

NASA Technical Reports Server (NTRS)

Latta, A. F.; Bowyer, J. M.; Fujita, T.

1979-01-01

This paper presents the performance and cost of four 10-MWe advanced solar thermal electric power plants sited in various regions of the continental United States. Each region has different insolation characteristics which result in varying collector field areas, plant performance, capital costs, and energy costs. The paraboloidal dish, central receiver, cylindrical parabolic trough, and compound parabolic concentrator (CPC) comprise the advanced concepts studied. This paper contains a discussion of the regional insolation data base, a description of the solar systems' performances and costs, and a presentation of a range for the forecast cost of conventional electricity by region and nationally over the next several decades.

Universal Features of Electron Dynamics in Solar Cells with TiO2 Contact: From Dye Solar Cells to Perovskite Solar Cells.

PubMed

Todinova, Anna; Idígoras, Jesús; Salado, Manuel; Kazim, Samrana; Anta, Juan A

2015-10-01

The electron dynamics of solar cells with mesoporous TiO2 contact is studied by electrochemical small-perturbation techniques. The study involved dye solar cells (DSC), solid-state perovskite solar cells (SSPSC), and devices where the perovskite acts as sensitizer in a liquid-junction device. Using a transport-recombination continuity equation we found that mid-frequency time constants are proper lifetimes that determine the current-voltage curve. This is not the case for the SSPSC, where a lifetime of ∼1 μs, 1 order of magnitude longer, is required to reproduce the current-voltage curve. This mismatch is attributed to the dielectric response on the mid-frequency component. Correcting for this effect, lifetimes lie on a common exponential trend with respect to open-circuit voltage. Electron transport times share a common trend line too. This universal behavior of lifetimes and transport times suggests that the main difference between the cells is the power to populate the mesoporous TiO2 contact with electrons.

My chaotic trajectory: A brief (personalized) history of solar-system dynamics.

NASA Astrophysics Data System (ADS)

Burns, Joseph A.

2014-05-01

I will use this opportunity to recall my professional career. Like many, I was drawn into the space program during the mid-60s and early 70s when the solar system’s true nature was being revealed. Previously, dynamical astronomy discussed the short-term, predictable motions of point masses; simultaneously, small objects (e.g., satellites, asteroids, dust) were thought boring rather than dynamically rich. Many of today’s most active research subjects were unknown: TNOs, planetary rings, exoplanets and debris disks. The continuing stream of startling findings by spacecraft, ground-based surveys and numerical simulations forced a renaissance in celestial mechanics, incorporating new dynamical paradigms and additional physics (e.g., energy loss, catastrophic events, radiation forces). My interests evolved as the space program expanded outward: dust, asteroids, natural satellites, rings; rotations, orbital evolution, origins. Fortunately for me, in the early days, elementary models with simple solutions were often adequate to gain a first-order explanation of many puzzles. One could be a generalist, always learning new things.My choice of research subjects was influenced greatly by: i) Cornell colleagues involved in space missions who shared results: the surprising diversity of planetary satellites, the unanticipated orbital and rotational dynamics of asteroids, the chaotic histories of solar system bodies, the non-intuitive behavior of dust and planetary rings, irregular satellites. ii) Teaching introductory courses in applied math, dynamics and planetary science encouraged understandable models. iii) The stimulation of new ideas owing to service at Icarus and on space policy forums. iv) Most importantly, excellent students and colleagues who pushed me into new research directions, and who then stimulated and educated me about those topics.If time allows, I will describe some of today’s puzzles for me and point out similarities between the past development in our

Design and integration of a solar AMTEC power system with an advanced global positioning satellite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, G.; Hunt, M.E.; Determan, W.R.

1996-12-31

A 1,200-W solar AMTEC (alkali metal thermal-to-electric conversion) power system concept was developed and integrated with an advanced global positioning system (GPS) satellite. The critical integration issues for the SAMTEC with the GPS subsystems included (1) packaging within the Delta 2 launch vehicle envelope, (2) deployment and start-up operations for the SAMTEC, (3) SAMTEC operation during all mission phases, (4) satellite field of view restrictions with satellite operations, and (5) effect of the SAMTEC requirements on other satellite subsystems. The SAMTEC power system was compared with a conventional planar solar array/battery power system to assess the differences in system weight,more » size, and operations. Features of the design include the use of an advanced multitube, vapor anode AMTEC cell design with 24% conversion efficiency, and a direct solar insolation receiver design with integral LiF salt canisters for energy storage to generate power during the maximum solar eclipse cycle. The modular generator design consists of an array of multitube AMTEC cells arranged into a parallel/series electrical network with built-in cell redundancy. The preliminary assessment indicates that the solar generator design is scalable over a 500 to 2,500-W range. No battery power is required during the operational phase of the GPS mission. SAMTEC specific power levels greater than 5 We/kg and 160 We/m{sup 2} are anticipated for a mission duration of 10 to 12 yr in orbits with high natural radiation backgrounds.« less

Interfacial dynamics and solar fuel formation in dye-sensitized photoelectrosynthesis cells.

PubMed

Song, Wenjing; Chen, Zuofeng; Glasson, Christopher R K; Hanson, Kenneth; Luo, Hanlin; Norris, Michael R; Ashford, Dennis L; Concepcion, Javier J; Brennaman, M Kyle; Meyer, Thomas J

2012-08-27

Dye-sensitized photoelectrosynthesis cells (DSPECs) represent a promising approach to solar fuels with solar-energy storage in chemical bonds. The targets are water splitting and carbon dioxide reduction by water to CO, other oxygenates, or hydrocarbons. DSPECs are based on dye-sensitized solar cells (DSSCs) but with photoexcitation driving physically separated solar fuel half reactions. A systematic basis for DSPECs is available based on a modular approach with light absorption/excited-state electron injection, and catalyst activation assembled in integrated structures. Progress has been made on catalysts for water oxidation and CO(2) reduction, dynamics of electron injection, back electron transfer, and photostability under conditions appropriate for water splitting. With added reductive scavengers, as surrogates for water oxidation, DSPECs have been investigated for hydrogen generation based on transient absorption and photocurrent measurements. Detailed insights are emerging which define kinetic and thermodynamic requirements for the individual processes underlying DSPEC performance. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Advanced Photovoltaic Solar Array (APSA) technology status and performance

NASA Technical Reports Server (NTRS)

Stella, Paul M.; Kurland, Richard M.

1991-01-01

In 1985, the Jet Propulsion Laboratory initiated the Advanced Photovoltaic Solar Array (APSA) program. The program objective is to demonstrate a producible array system by the early 1990s with a specific performance of at least 130 W/kG (beginning-of-life) as an intermediate milestone towards the long range goal of 300 W/kG. The APSA performance represents an approximately four-fold improvement over existing rigid array technology and a doubling of the performance of the first generation NASA/OAST SAFE flexible blanket array of the early 1980s.

Comparison of advanced engines for parabolic dish solar thermal power plants

NASA Technical Reports Server (NTRS)

Fujita, T.; Bowyer, J. M.; Gajanana, B. C.

1980-01-01

A paraboloidal dish solar thermal power plant produces electrical energy by a two-step conversion process. The collector subsystem is composed of a two-axis tracking paraboloidal concentrator and a cavity receiver. The concentrator focuses intercepted sunlight (direct, normal insolation) into a cavity receiver whose aperture encircles the focal point of the concentrator. At the internal wall of the receiver the electromagnetic radiation is converted to thermal energy. A heat engine/generator assembly then converts the thermal energy captured by the receiver to electricity. Developmental activity has been concentrated on small power modules which employ 11- to 12-meter diameter dishes to generate nominal power levels of approximately 20 kWe. A comparison of advanced heat engines for the dish power module is presented in terms of the performance potential of each engine with its requirements for advanced technology development. Three advanced engine possibilities are the Brayton (gas turbine), Brayton/Rankine combined cycle, and Stirling engines.

Origin of Outer Solar System

NASA Technical Reports Server (NTRS)

Holman, Matthew J.; Lindstrom, David (Technical Monitor)

2005-01-01

Our ongoing research program combines extensive deep and wide-field observations using a variety of observational platforms with numerical studies of the dynamics of small bodies in the outer solar system in order to advance the main scientific goals of the community studying the Kuiper belt and the outer solar system. These include: (1) determining the relative populations of the known classes of KBOs as well as other possible classes; ( 2 ) determining the size distributions or luminosity function of the individual populations or the Kuiper belt as a whole; (3) determining the inclinations distributions of these populations; (4) establishing the radial extent of the Kuiper belt; ( 5 ) measuring and relating the physical properties of different types of KBOs to those of other solar system bodies; and, (6) completing our systematic inventory of the satellites of the outer planets.

800 Hours of Operational Experience from a 2 kW(sub e) Solar Dynamic System

NASA Technical Reports Server (NTRS)

Shaltens, Richard K.; Mason, Lee S.

1999-01-01

From December 1994 to September 1998, testing with a 2 kW(sub e) Solar Dynamic power system resulted in 33 individual tests, 886 hours of solar heating, and 783 hours of power generation. Power generation ranged from 400 watts to over 2 kW(sub e), and SD system efficiencies have been measured up to 17 per cent, during simulated low-Earth orbit operation. Further, the turbo-alternator-compressors successfully completed 100 start/stops on foil bearings. Operation was conducted in a large thermal/vacuum facility with a simulated Sun at the NASA Lewis Research Center. The Solar Dynamic system featured a closed Brayton conversion unit integrated with a solar heat receiver, which included thermal energy storage for continuous power output through a typical low-Earth orbit. Two power conversion units and three alternator configurations were used during testing. This paper will review the test program, provide operational and performance data, and review a number of technology issues.

Evaluation of thermal control coatings for use on solar dynamic radiators in low earth orbit

NASA Technical Reports Server (NTRS)

Dever, Joyce A.; Rodriguez, Elvin; Slemp, Wayne S.; Stoyack, Joseph E.

1991-01-01

Thermal control coatings with high thermal emittance and low solar absorptance are needed for Space Station Freedom (SSF) solar dynamic power module radiator (SDR) surfaces for efficient heat rejection. Additionally, these coatings must be durable to low earth orbital (LEO) environmental effects of atomic oxygen, ultraviolet radiation and deep thermal cycles which occur as a result of start-up and shut-down of the solar dynamic power system. Eleven candidate coatings were characterized for their solar absorptance and emittance before and after exposure to ultraviolet (UV) radiation (200 to 400 nm), vacuum UV (VUV) radiation (100 to 200 nm) and atomic oxygen. Results indicated that the most durable and best performing coatings were white paint thermal control coatings Z-93, zinc oxide pigment in potassium silicate binder, and YB-71, zinc orthotitanate pigment in potassium silicate binder. Optical micrographs of these materials exposed to the individual environmental effects of atomic oxygen and vacuum thermal cycling showed that no surface cracking occurred.

Evaluation of thermal control coatings for use on solar dynamic radiators in low Earth orbit

NASA Technical Reports Server (NTRS)

Dever, Joyce A.; Rodriguez, Elvin; Slemp, Wayne S.; Stoyack, Joseph E.

1991-01-01

Thermal control coatings with high thermal emittance and low solar absorptance are needed for Space Station Freedom (SSF) solar dynamic power module radiator (SDR) surfaces for efficient heat rejection. Additionally, these coatings must be durable to low earth orbital (LEO) environmental effects of atomic oxygen, ultraviolet radiation and deep thermal cycles which occur as a result of start-up and shut-down of the solar dynamic power system. Eleven candidate coatings were characterized for their solar absorptance and emittance before and after exposure to ultraviolet (UV) radiation (200 to 400 nm), vacuum UV (VUV) radiation (100 to 200 nm) and atomic oxygen. Results indicated that the most durable and best performing coatings were white paint thermal control coatings Z-93, zinc oxide pigment in potassium silicate binder, and YB-71, zinc orthotitanate pigment in potassium silicate binder. Optical micrographs of these materials exposed to the individual environmental effects of atomic oxygen and vacuum thermal cycling showed that no surface cracking occurred.

NASA's SDO Sees Solar Flares

NASA Image and Video Library

2017-12-08

A second X-class flare of June 10, 2014, appears as a bright flash on the left side of this image from NASA’s Solar Dynamics Observatory. This image shows light in the 193-angstrom wavelength, which is typically colorized in yellow. It was captured at 8:55 a.m EDT, just after the flare peaked. Credit: NASA/SDO NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Theoretical studies of the physics of the solar atmosphere

NASA Technical Reports Server (NTRS)

Hollweg, Joseph V.

1992-01-01

Significant advances in our theoretical basis for understanding several physical processes related to dynamical phenomena on the sun were achieved. We have advanced a new model for spicules and fibrils. We have provided a simple physical view of resonance absorption of MHD surface waves; this allowed an approximate mathematical procedure for obtaining a wealth of new analytical results which we applied to coronal heating and p-mode absorption at magnetic regions. We provided the first comprehensive models for the heating and acceleration of the transition region, corona, and solar wind. We provided a new view of viscosity under coronal conditions. We provided new insights into Alfven wave propagation in the solar atmosphere. And recently we have begun work in a new direction: parametric instabilities of Alfven waves.

The 2-8 GHz solar dynamic spectra and polarization measurement feasibility study

NASA Technical Reports Server (NTRS)

Haddock, F. T.

1971-01-01

The preliminary system design of a Solar Microwave Spectrograph (SMS) is presented. This design resulted from a study to determine the feasibility of measuring solar polarization and dynamic spectra over the range of two to eight GHz, using broadband radio frequency instrumentation and rapid recording equipment in conjunction with radio telescopes. The scientific value of the proposed SMS instrument is discussed, with remarks concerning data reduction and analysis and a presentation of the engineering plan to implement the SMS system.

Solar irradiance dictates settlement timing and intensity of marine mussels

PubMed Central

Fuentes-Santos, Isabel; Labarta, Uxío; Álvarez-Salgado, X. Antón; Fernández-Reiriz, Mª José

2016-01-01

Identifying the environmental factors driving larval settlement processes is crucial to understand the population dynamics of marine invertebrates. This work aims to go a step ahead and predict larval presence and intensity. For this purpose we consider the influence of solar irradiance, wind regime and continental runoff on the settlement processes. For the first time, we conducted a 5-years weekly monitoring of Mytilus galloprovincialis settlement on artificial suspended substrates, which allowed us to search for interannual variability in the settlement patterns. Comparison between the seasonal pattern of larval settlement and solar irradiance, as well as the well-known effect of solar irradiance on water temperature and food availability, suggest that solar irradiance indirectly influences the settlement process, and support the use of this meteorological variable to predict settlement occurrence. Our results show that solar irradiance allows predicting the beginning and end of the settlement cycle a month in advance: Particularly we have observed that solar irradiance during late winter indirectly drives the timing and intensity of the settlement onset, Finally, a functional generalise additive model, which considers the influence of solar irradiance and continental runoff on the settlement process, provides an accurate prediction of settlement intensity a fortnight in advance. PMID:27384527

Solar irradiance dictates settlement timing and intensity of marine mussels

NASA Astrophysics Data System (ADS)

Fuentes-Santos, Isabel; Labarta, Uxío; Álvarez-Salgado, X. Antón; Fernández-Reiriz, Mª José

2016-07-01

Identifying the environmental factors driving larval settlement processes is crucial to understand the population dynamics of marine invertebrates. This work aims to go a step ahead and predict larval presence and intensity. For this purpose we consider the influence of solar irradiance, wind regime and continental runoff on the settlement processes. For the first time, we conducted a 5-years weekly monitoring of Mytilus galloprovincialis settlement on artificial suspended substrates, which allowed us to search for interannual variability in the settlement patterns. Comparison between the seasonal pattern of larval settlement and solar irradiance, as well as the well-known effect of solar irradiance on water temperature and food availability, suggest that solar irradiance indirectly influences the settlement process, and support the use of this meteorological variable to predict settlement occurrence. Our results show that solar irradiance allows predicting the beginning and end of the settlement cycle a month in advance: Particularly we have observed that solar irradiance during late winter indirectly drives the timing and intensity of the settlement onset, Finally, a functional generalise additive model, which considers the influence of solar irradiance and continental runoff on the settlement process, provides an accurate prediction of settlement intensity a fortnight in advance.

Advanced planetary studies

NASA Technical Reports Server (NTRS)

1977-01-01

Results of planetary advanced studies and planning support are summarized. The scope of analyses includes cost estimation research, planetary mission performance, penetrator advanced studies, Mercury mission transport requirements, definition of super solar electric propulsion/solar sail mission discriminators, and advanced planning activities.

Coupled orbit-attitude dynamics and relative state estimation of spacecraft near small Solar System bodies

NASA Astrophysics Data System (ADS)

Misra, Gaurav; Izadi, Maziar; Sanyal, Amit; Scheeres, Daniel

2016-04-01

The effects of dynamical coupling between the rotational (attitude) and translational (orbital) motion of spacecraft near small Solar System bodies is investigated. This coupling arises due to the weak gravity of these bodies, as well as solar radiation pressure. The traditional approach assumes a point-mass spacecraft model to describe the translational motion of the spacecraft, while the attitude motion is considered to be completely decoupled from the translational motion. The model used here to describe the rigid-body spacecraft dynamics includes the non-uniform rotating gravity field of the small body up to second degree and order along with the attitude dependent terms, solar tide, and solar radiation pressure. This model shows that the second degree and order gravity terms due to the small body affect the dynamics of the spacecraft to the same extent as the orbit-attitude coupling due to the primary gravity (zeroth order) term. Variational integrators are used to simulate the dynamics of both the rigid spacecraft and the point mass. The small bodies considered here are modeled after Near-Earth Objects (NEO) 101955 Bennu, and 25143 Itokawa, and are assumed to be triaxial ellipsoids with uniform density. Differences in the numerically obtained trajectories of a rigid spacecraft and a point mass are then compared, to illustrate the impact of the orbit-attitude coupling on spacecraft dynamics in proximity of small bodies. Possible implications on the performance of model-based spacecraft control and on the station-keeping budget, if the orbit-attitude coupling is not accounted for in the model of the dynamics, are also discussed. An almost globally asymptotically stable motion estimation scheme based solely on visual/optical feedback that estimates the relative motion of the asteroid with respect to the spacecraft is also obtained. This estimation scheme does not require a model of the dynamics of the asteroid, which makes it perfectly suited for asteroids whose

The Structure and Dynamics of the Solar Corona

NASA Technical Reports Server (NTRS)

Mikic, Zoran

2000-01-01

This report covers technical progress during the third year of the NASA Space Physics Theory contract "The Structure and Dynamics of the Solar Corona," between NASA and Science Applications International Corporation, and covers the period June 16, 1998 to August 15, 1999. This is also the final report for this contract. Under this contract SAIC, the University of California, Irvine (UCI), and the Jet Propulsion Laboratory (JPL), have conducted research into theoretical modeling of active regions, the solar corona, and the inner heliosphere, using the MHD model. During the three-year duration of this contract we have published 49 articles in the scientific literature. These publications are listed in Section 3 of this report. In the Appendix we have attached reprints of selected articles. We summarize our progress during the third year of the contract. Full descriptions of our work can be found in the cited publications, a few of which are attached to this report.

A practical six-degree of freedom solar sail dynamics model for optimizing solar sail trajectories with torque constraints

NASA Technical Reports Server (NTRS)

Lisano, Michael E.

2004-01-01

Controlled flight of a solar sail-propelled spacecraft ('sailcraft') is a six-degree-of-freedom dynamics problem. Current state-of-the-art tools that simulate and optimize the trajectories flown by sailcraft do not treat the full kinetic (i.e. force and torque-constrained) motion, instead treating a discrete history of commanded sail attitudes, and either neglecting the sail attitude motion over an integration timestep, or treating the attitude evolution kinematically with a spline or similar treatment. The present paper discusses an aspect of developing a next generation sailcraf trajectory designing optimization tool JPL, for NASA's Solar Sail Spaceflight Simulation Software (SS). The aspect discussed in an experimental approach to modeling full six-degree-of-freedom kinetic motion of a solar sail in a trajectory propagator. Early results from implementing this approach in a new trajectory propagation tool are given.

Utilization of Solar Dynamics Observatory space weather digital image data for comparative analysis with application to Baryon Oscillation Spectroscopic Survey

NASA Astrophysics Data System (ADS)

Shekoyan, V.; Dehipawala, S.; Liu, Ernest; Tulsee, Vivek; Armendariz, R.; Tremberger, G.; Holden, T.; Marchese, P.; Cheung, T.

2012-10-01

Digital solar image data is available to users with access to standard, mass-market software. Many scientific projects utilize the Flexible Image Transport System (FITS) format, which requires specialized software typically used in astrophysical research. Data in the FITS format includes photometric and spatial calibration information, which may not be useful to researchers working with self-calibrated, comparative approaches. This project examines the advantages of using mass-market software with readily downloadable image data from the Solar Dynamics Observatory for comparative analysis over with the use of specialized software capable of reading data in the FITS format. Comparative analyses of brightness statistics that describe the solar disk in the study of magnetic energy using algorithms included in mass-market software have been shown to give results similar to analyses using FITS data. The entanglement of magnetic energy associated with solar eruptions, as well as the development of such eruptions, has been characterized successfully using mass-market software. The proposed algorithm would help to establish a publicly accessible, computing network that could assist in exploratory studies of all FITS data. The advances in computer, cell phone and tablet technology could incorporate such an approach readily for the enhancement of high school and first-year college space weather education on a global scale. Application to ground based data such as that contained in the Baryon Oscillation Spectroscopic Survey is discussed.

Temperature control in a solar collector field using Filtered Dynamic Matrix Control.

PubMed

Lima, Daniel Martins; Normey-Rico, Julio Elias; Santos, Tito Luís Maia

2016-05-01

This paper presents the output temperature control of a solar collector field of a desalinization plant using the Filtered Dynamic Matrix Control (FDMC). The FDMC is a modified controller based on the Dynamic Matrix Control (DMC), a predictive control strategy widely used in industry. In the FDMC, a filter is used in the prediction error, which allows the modification of the robustness and disturbance rejection characteristics of the original algorithm. The implementation and tuning of the FDMC are simple and maintain the advantages of DMC. Several simulation results using a validated model of the solar plant are presented considering different scenarios. The results are also compared to nonlinear control techniques, showing that FDMC, if properly tuned, can yield similar results to more complex control algorithms. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Dynamic Power Spectral Analysis of Solar Measurements from Photospheric, Chromospheric, and Coronal Sources

NASA Technical Reports Server (NTRS)

Bouwer, S. D.; Pap, J.; Donnelly, R. F.

1990-01-01

An important aspect in the power spectral analysis of solar variability is the quasistationary and quasiperiodic nature of solar periodicities. In other words, the frequency, phase, and amplitude of solar periodicities vary on time scales ranging from active region lifetimes to solar cycle time scales. Here, researchers employ a dynamic, or running, power spectral density analysis to determine many periodicities and their time-varying nature in the projected area of active sunspot groups (S sub act). The Solar Maximum Mission/Active Cavity Radiometer Irradiance Monitor (SMM/ACRIM) total solar irradiance (S), the Nimbus-7 MgII center-to-wing ratio (R (MgII sub c/w)), the Ottawa 10.7 cm flux (F sub 10.7), and the GOES background x ray flux (X sub b) for the maximum, descending, and minimum portions of solar cycle 21 (i.e., 1980 to 1986) are used. The technique dramatically illustrates several previously unrecognized periodicities. For example, a relatively stable period at about 51 days has been found in those indices which are related to emerging magnetic fields. The majority of solar periodicities, particularly around 27, 150 and 300 days, are quasiperiodic because they vary in amplitude and frequency throughout the solar cycle. Finally, it is shown that there are clear differences between the power spectral densities of solar measurements from photospheric, chromospheric, and coronal sources.

Flux concentrations on solar dynamic components due to mispointing

NASA Technical Reports Server (NTRS)

Rylicki, Daniel S.

1992-01-01

Mispointing of the solar dynamic (SD) concentrator designed for use on Space Station Freedom (SSF) causes the optical axis of the concentrator to be nonparallel to the incoming rays from the Sun. This causes solar flux not to be focused into the aperture hole of the receiver and may position the flux on other SSF components. A Rocketdyne analysis has determined the thermal impact of off-axis radiation due to mispointing on elements of the SD module and photovoltaic (PV) arrays. The conclusion was that flux distributions on some of the radiator components, the two-axis gimbal rings, the truss, and the PV arrays could present problems. The OFFSET computer code was used at Lewis Research Center to further investigate these flux distributions incident on components. The Lewis study included distributions for a greater range of mispoint angles than the Rocketdyne study.

Advances in Perovskite Solar Cells

PubMed Central

Zuo, Chuantian; Bolink, Henk J.; Han, Hongwei; Huang, Jinsong

2016-01-01

Organolead halide perovskite materials possess a combination of remarkable optoelectronic properties, such as steep optical absorption edge and high absorption coefficients, long charge carrier diffusion lengths and lifetimes. Taken together with the ability for low temperature preparation, also from solution, perovskite‐based devices, especially photovoltaic (PV) cells have been studied intensively, with remarkable progress in performance, over the past few years. The combination of high efficiency, low cost and additional (non‐PV) applications provides great potential for commercialization. Performance and applications of perovskite solar cells often correlate with their device structures. Many innovative device structures were developed, aiming at large‐scale fabrication, reducing fabrication cost, enhancing the power conversion efficiency and thus broadening potential future applications. This review summarizes typical structures of perovskite solar cells and comments on novel device structures. The applications of perovskite solar cells are discussed. PMID:27812475

Simplified Calculation Of Solar Fluxes In Solar Receivers

NASA Technical Reports Server (NTRS)

Bhandari, Pradeep

1990-01-01

Simplified Calculation of Solar Flux Distribution on Side Wall of Cylindrical Cavity Solar Receivers computer program employs simple solar-flux-calculation algorithm for cylindrical-cavity-type solar receiver. Results compare favorably with those of more complicated programs. Applications include study of solar energy and transfer of heat, and space power/solar-dynamics engineering. Written in FORTRAN 77.

Dynamical buoyancy of hydrodynamic eddies. [in solar atmosphere

NASA Technical Reports Server (NTRS)

Parker, E. N.

1991-01-01

The dynamical pressure reduction within a vortex tube produces both a tension along the tube and a general buoyancy, analogous to magnetic flux tubes. The dynamical buoyancy causes convective cells to rise at speeds comparable to the rms fluid velocity within the cell. Consequently, the convective cells in a stratified atmosphere are more active than indicated by the standard anelastic approximation. The coherent convective cells at each level actively crowd upward into the convective cells above, elbowing weaker cells out of the way and flattening themselves and others against the upper surface of the convective region. These effects can be seen in the recent SOUP observations of the solar granulation. Deeper in the convective zone the inhomogeneity of the buoyancy may explain the random character of the convective motions that turns up in recent numerical simulations.

Solar Arches

NASA Image and Video Library

2017-12-08

The magnetic field lines between a pair of active regions formed a beautiful set of swaying arches, seen in this footage captured by NASA’s Solar Dynamics Observatory on April 24-26, 2017. The arches are traced out by charged particles spinning along the magnetic field lines. These arches, which form a connection between regions of opposite magnetic polarity, are visible in exquisite detail in this wavelength of extreme ultraviolet light. Extreme ultraviolet light is typically invisible to our eyes, but is colorized here in gold. Read more: go.nasa.gov/2pGgYZt NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

On the Dynamics of Small-Scale Solar Magnetic Elements

NASA Technical Reports Server (NTRS)

Berger, T. E.; Title, A. M.

1996-01-01

We report on the dynamics of the small-scale solar magnetic field, based on analysis of very high resolution images of the solar photosphere obtained at the Swedish Vacuum Solar Telescope. The data sets are movies from 1 to 4 hr in length, taken in several wavelength bands with a typical time between frames of 20 s. The primary method of tracking small-scale magnetic elements is with very high contrast images of photospheric bright points, taken through a 12 A bandpass filter centered at 4305 A in the Fraunhofer 'G band.' Previous studies have established that such bright points are unambiguously associated with sites of small-scale magnetic flux in the photosphere, although the details of the mechanism responsible for the brightening of the flux elements remain uncertain. The G band bright points move in the intergranular lanes at speeds from 0.5 to 5 km/s. The motions appear to be constrained to the intergranular lanes and are primarily driven by the evolution of the local granular convection flow field. Continual fragmentation and merging of flux is the fundamental evolutionary mode of small-scale magnetic structures in the solar photosphere. Rotation and folding of chains or groups of bright points are also observed. The timescale for magnetic flux evolution in active region plage is on the order of the correlation time of granulation (typically 6-8 minutes), but significant morphological changes can occur on timescales as short as 100 S. Smaller fragments are occasionally seen to fade beyond observable contrast. The concept of a stable, isolated subarcsecond magnetic 'flux tube' in the solar photosphere is inconsistent with the observations presented here.

2 kWe Solar Dynamic Ground Test Demonstration Project. Volume 3; Fabrication and Test Report

NASA Technical Reports Server (NTRS)

Alexander, Dennis

1997-01-01

The Solar Dynamic Ground Test Demonstration (SDGTD) project has successfully designed and fabricated a complete solar-powered closed Brayton electrical power generation system and tested it in a relevant thermal vacuum facility at NASA Lewis Research Center (LeRC). In addition to completing technical objectives, the project was completed 3-l/2 months early, and under budget.

Integrated dynamic analysis simulation of space stations with controllable solar arrays (supplemental data and analyses)

NASA Technical Reports Server (NTRS)

Heinrichs, J. A.; Fee, J. J.

1972-01-01

Space station and solar array data and the analyses which were performed in support of the integrated dynamic analysis study. The analysis methods and the formulated digital simulation were developed. Control systems for space station altitude control and solar array orientation control include generic type control systems. These systems have been digitally coded and included in the simulation.

Magnetohydrodynamic Modeling of Solar Coronal Dynamics with an Initial Non-force-free Magnetic Field

NASA Astrophysics Data System (ADS)

Prasad, A.; Bhattacharyya, R.; Kumar, Sanjay

2017-05-01

The magnetic fields in the solar corona are generally neither force-free nor axisymmetric and have complex dynamics that are difficult to characterize. Here we simulate the topological evolution of solar coronal magnetic field lines (MFLs) using a magnetohydrodynamic model. The simulation is initialized with a non-axisymmetric non-force-free magnetic field that best correlates with the observed vector magnetograms of solar active regions (ARs). To focus on these ideas, simulations are performed for the flaring AR 11283 noted for its complexity and well-documented dynamics. The simulated dynamics develops as the initial Lorentz force pushes the plasma and facilitates successive magnetic reconnections at the two X-type null lines present in the initial field. Importantly, the simulation allows for the spontaneous development of mass flow, unique among contemporary works, that preferentially reconnects field lines at one of the X-type null lines. Consequently, a flux rope consisting of low-lying twisted MFLs, which approximately traces the major polarity inversion line, undergoes an asymmetric monotonic rise. The rise is attributed to a reduction in the magnetic tension force at the region overlying the rope, resulting from the reconnection. A monotonic rise of the rope is in conformity with the standard scenario of flares. Importantly, the simulated dynamics leads to bifurcations of the flux rope, which, being akin to the observed filament bifurcation in AR 11283, establishes the appropriateness of the initial field in describing ARs.

Magnetohydrodynamic Modeling of Solar Coronal Dynamics with an Initial Non-force-free Magnetic Field

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prasad, A.; Bhattacharyya, R.; Kumar, Sanjay

The magnetic fields in the solar corona are generally neither force-free nor axisymmetric and have complex dynamics that are difficult to characterize. Here we simulate the topological evolution of solar coronal magnetic field lines (MFLs) using a magnetohydrodynamic model. The simulation is initialized with a non-axisymmetric non-force-free magnetic field that best correlates with the observed vector magnetograms of solar active regions (ARs). To focus on these ideas, simulations are performed for the flaring AR 11283 noted for its complexity and well-documented dynamics. The simulated dynamics develops as the initial Lorentz force pushes the plasma and facilitates successive magnetic reconnections atmore » the two X-type null lines present in the initial field. Importantly, the simulation allows for the spontaneous development of mass flow, unique among contemporary works, that preferentially reconnects field lines at one of the X-type null lines. Consequently, a flux rope consisting of low-lying twisted MFLs, which approximately traces the major polarity inversion line, undergoes an asymmetric monotonic rise. The rise is attributed to a reduction in the magnetic tension force at the region overlying the rope, resulting from the reconnection. A monotonic rise of the rope is in conformity with the standard scenario of flares. Importantly, the simulated dynamics leads to bifurcations of the flux rope, which, being akin to the observed filament bifurcation in AR 11283, establishes the appropriateness of the initial field in describing ARs.« less

Dynamical Networks Characterization of Geomagnetic Substorms and Transient Response to the Solar Wind State.

NASA Astrophysics Data System (ADS)

Chapman, S. C.; Dods, J.; Gjerloev, J. W.

2017-12-01

Observations of how the solar wind interacts with earth's magnetosphere, and its dynamical response, are increasingly becoming a data analytics challenge. Constellations of satellites observe the solar corona, the upstream solar wind and throughout earth's magnetosphere. These data are multipoint in space and extended in time, so in principle are ideal for study using dynamical networks to characterize the full time evolving spatial pattern. We focus here on analysis of data from the full set of 100+ auroral ground based magnetometer stations that have been collated by SuperMAG. Spatio-temporal patterns of correlation between the magnetometer time series can be used to form a dynamical network [1]. The properties of the network can then be captured by (time dependent) network parameters. This offers the possibility of characterizing detailed spatio-temporal pattern by a few parameters, so that many events can then be compared [2] with each other. Whilst networks are in widespread use in the data analytics of societal and commercial data, there are additional challenges in their application to physical timeseries. Determining whether two nodes (here, ground based magnetometer stations) are connected in a network (seeing the same dynamics) requires normalization w.r.t. the detailed sensitivities and dynamical responses of specific observing stations and seasonal conductivity variations and we have developed methods to achieve this dynamical normalization. The detailed properties of the network capture time dependent spatial correlation in the magnetometer responses and we will show how this can be used to infer a transient current system response to magnetospheric activity. [l] Dods et al, J. Geophys. Res 120, doi:10.1002/2015JA02 (2015). [2] Dods et al, J. Geophys. Res. 122, doi:10.1002/2016JA02 (2017).

Advanced Solar Receivers

NASA Technical Reports Server (NTRS)

Owen, W. A.

1984-01-01

Low thermal efficiencies in solar receivers are discussed in terms of system design. It is recommended that careful attention be given to the overall thermal systems design, especially to conductive losses about the window and areas of relatively thin insulation. If the cavity design is carefully managed to insure a small, minimally reradiating aperture, the goal of a very high efficiency cavity receiver is a realistic one.

High Current ESD Test of Advanced Triple Junction Solar Array Coupon

NASA Technical Reports Server (NTRS)

Wright, Kenneth H., Jr.; Schneider, Todd A.; Vaughn, Jason A.; Hoang, Bao; Wong, Frankie

2015-01-01

A test was conducted on an Advanced Triple Junction (ATJ) coupon that was part of a risk reduction effort in the development of a high-powered solar array design by SSL. The ATJ coupon was a small, 4-cell, two-string configuration that has served as the basic test coupon design used in previous SSL environmental aging campaigns. The coupon has many attributes of the flight design; e.g., substrate structure with graphite face sheets, integrated by-pass diodes, cell interconnects, RTV grout, wire routing, etc. The objective of the present test was to evaluate the performance of the coupon after being subjected to induced electrostatic discharge testing at two string voltages (100 V, 150 V) and four array current (1.65 A, 2.0 A, 2.475 A, and 3.3 A). An ESD test circuit, unique to SSL solar array design, was built that simulates the effect of missing cells and strings in a full solar panel with special primary arc flashover circuitry. A total of 73 primary arcs were obtained that included 7 temporary sustained arcs (TSA) events. The durations of the TSAs ranged from 50 micros to 2.9 ms. All TSAs occurred at a string voltage of 150 V. Post-test Large Area Pulsed Solar Simulator (LAPSS), Dark I-V, and By-Pass Diode tests showed that no degradation occurred due to the TSA events. In addition, the post-test insulation resistance measured was > 50 G-ohms between cells and substrate. These test results indicate a robust design for application to a high-current, high-power mission application.

High Current ESD Test of Advanced Triple Junction Solar Array Coupon

NASA Technical Reports Server (NTRS)

Wright, K. H.; Schneider, T. A.; Vaughn, J. A.; Hoang, B.; Wong, F.

2014-01-01

A test was conducted on an Advanced Triple Junction (ATJ) coupon that was part of a risk reduction effort in the development of a high-powered solar array design by SSL. The ATJ coupon was a small, 4-cell, two-string configuration that has served as the basic test coupon design used in previous SSL environmental aging campaigns. The coupon has many attributes of the flight design; e.g., substrate structure with graphite face sheets, integrated by-pass diodes, cell interconnects, RTV grout, wire routing, etc. The objective of the present test was to evaluate the performance of the coupon after being subjected to induced electrostatic discharge testing at two string voltages (100 V, 150 V) and four array current (1.65 A, 2.0 A, 2.475 A, and 3.3 A). An ESD test circuit, unique to SSL solar array design, was built that simulates the effect of missing cells and strings in a full solar panel with special primary arc flashover circuitry. A total of 73 primary arcs were obtained that included 7 temporary sustained arcs (TSA) events. The durations of the TSAs ranged from 50 µs to 2.9 ms. All TSAs occurred at a string voltage of 150 V. Post-test Large Area Pulsed Solar Simulator (LAPSS), Dark I-V, and By-Pass Diode tests showed that no degradation occurred due to the TSA events. In addition, the post-test insulation resistance measured was > 50 G-ohms between cells and substrate. These test results indicate a robust design for application to a high-current, high-power mission application.

Advanced power cycles and configurations for solar towers: Modeling and optimization of the decoupled solar combined cycle concept

NASA Astrophysics Data System (ADS)

García-Barberena, Javier; Olcoz, Asier; Sorbet, Fco. Javier

2017-06-01

CSP technologies are essential to allow large shares of renewables into the grid due to their unique ability to cope with the large variability of the energy resource by means of technically and economically feasible thermal energy storage (TES) systems. However, there is still the need and sought to achieve technological breakthroughs towards cost reductions and increased efficiencies. For this, research on advanced power cycles, like the Decoupled Solar Combined Cycle (DSCC) is, are regarded as a key objective. The DSCC concept is, basically, a Combined Brayton-Rankine cycle in which the bottoming cycle is decoupled from the operation of the topping cycle by means of an intermediate storage system. According to this concept, one or several solar towers driving a solar air receiver and a Gas Turbine (Brayton cycle) feed through their exhaust gasses a single storage system and bottoming cycle. This general concept benefits from a large flexibility in its design. On the one hand, different possible schemes related to number and configuration of solar towers, storage systems media and configuration, bottoming cycles, etc. are possible. On the other, within a specific scheme a large number of design parameters can be optimized, including the solar field size, the operating temperatures and pressures of the receiver, the power of the Brayton and Rankine cycles, the storage capacity and others. Heretofore, DSCC plants have been analyzed by means of simple steady-state models with pre-stablished operating parameters in the power cycles. In this work, a detailed transient simulation model for DSCC plants has been developed and is used to analyze different DSCC plant schemes. For each of the analyzed plant schemes, a sensitivity analysis and selection of the main design parameters is carried out. Results show that an increase in annual solar to electric efficiency of 30% (from 12.91 to 16.78) can be achieved by using two bottoming Rankine cycles at two different

Solar and interplanetary dynamics; Proceedings of the Symposium, Harvard University, Cambridge, Mass., August 27-31, 1979

NASA Technical Reports Server (NTRS)

Dryer, M. (Editor); Tandberg-Hanssen, E.

1980-01-01

The symposium focuses on solar phenomena as the source of transient events propagating through the solar system, and theoretical and observational assessments of the dynamic processes involved in these events. The topics discussed include the life history of coronal structures and fields, coronal and interplanetary responses to long time scale phenomena, solar transient phenomena affecting the corona and interplanetary medium, coronal and interplanetary responses to short time scale phenomena, and future directions.

The Solar Dynamics Observatory: Your On-Orbit Eye on the Sun

NASA Technical Reports Server (NTRS)

Pesnell, W. Dean

2011-01-01

The Solar Dynamics Observatory (SDO) was launched on February 11, 2010 into the partly cloudy skies above Cape Canaveral, Florida. Over the next month SDO moved into a 28 degree inclined geosynchronous orbit at the longitude of the ground station in New Mexico. SDO is the first Space Weather Mission in NASA's Living With a Star Program. SDO's main goal is to understand and predict those solar variations that influence life on Earth and our technological systems. The SDO science investigations will determine how the Sun's magnetic field is generated and structured, how this stored magnetic energy is released into the heliosphere as the solar wind, energetic particles, and variations in the solar irradiance. The SDO mission consists of three scientific investigations (AIA, EVE, and HMI), a spacecraft bus, and a dedicated Ka-band ground station to handle the 150 Mbps data flow. SDO continues a long tradition of NASA missions providing calibrated solar spectral irradiance data, in this case using multiple measurements of the irradiance and rocket underflights of the spacecraft. The other instruments on SDO will be used to explain and develop predictive models of the solar spectral irradiance in the extreme ultraviolet. Science teams at LMSAL, LASP, and Stanford are responsible for processing, analyzing, distributing, and archiving the science data. We will talk about the launch of SDO and describe the data and science it is providing to NASA.

Development of processing procedures for advanced silicon solar cells. [antireflection coatings and short circuit currents

NASA Technical Reports Server (NTRS)

Scott-Monck, J. A.; Stella, P. M.; Avery, J. E.

1975-01-01

Ten ohm-cm silicon solar cells, 0.2 mm thick, were produced with short circuit current efficiencies up to thirteen percent and using a combination of recent technical advances. The cells were fabricated in conventional and wraparound contact configurations. Improvement in cell collection efficiency from both the short and long wavelengths region of the solar spectrum was obtained by coupling a shallow junction and an optically transparent antireflection coating with back surface field technology. Both boron diffusion and aluminum alloying techniques were evaluated for forming back surface field cells. The latter method is less complicated and is compatible with wraparound cell processing.

Extreme Ultraviolet Variability Experiment (EVE) on the Solar Dynamics Observatory (SDO): Overview of Science Objectives, Instrument Design, Data Products, and Model Developments

NASA Technical Reports Server (NTRS)

Woods, T. N.; Eparvier, F. G.; Hock, R.; Jones, A. R.; Woodraska, D.; Judge, D.; Didkovsky, L.; Lean, J.; Mariska, J.; Warren, H.;

Solar Golden Arches

NASA Image and Video Library

2017-12-08

The magnetic field lines between a pair of active regions formed a beautiful set of swaying arches, seen in this footage captured by NASA’s Solar Dynamics Observatory on April 24-26, 2017. The arches are traced out by charged particles spinning along the magnetic field lines. These arches, which form a connection between regions of opposite magnetic polarity, are visible in exquisite detail in this wavelength of extreme ultraviolet light. Extreme ultraviolet light is typically invisible to our eyes, but is colorized here in gold. Credit: NASA/Goddard/SDO NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Exploring dynamic events in the solar corona

NASA Astrophysics Data System (ADS)

Downs, Cooper James

With the advent of modern computational technology it is now becoming the norm to employ detailed 3D computer models as empirical tools that directly account for the inhomogeneous nature of the Sun-Heliosphere environment. The key advantage of this approach lies in the ability to compare model results directly to observational data and to use a successful comparison (or lack thereof) to glean information on the underlying physical processes. Using extreme ultraviolet waves (EUV waves) as the overarching scientific driver, we apply this observation modeling approach to study the complex dynamics of the magnetic and thermodynamic structures that are observed in the low solar corona. Representing a highly non-trivial effort, this work includes three main scientific thrusts: an initial modeling effort and two EUV wave case-studies. First we document the development of the new Low Corona (LC) model, a 3D time-dependent thermodynamic magnetohydrodynamic (MHD) model implemented within the Space Weather Modeling Framework (SWMF). Observation synthesis methods are integrated within the LC model, which provides the ability to compare model results directly to EUV imaging observations taken by spacecraft. The new model is then used to explore the dynamic interplay between magnetic structures and thermodynamic energy balance in the corona that is caused by coronal heating mechanisms. With the model development complete, we investigate the nature of EUV waves in detail through two case-studies. Starting with the 2008 March 25 event, we conduct a series of numerical simulations that independently vary fundamental parameters thought to govern the physical mechanisms behind EUV waves. Through the subsequent analysis of the 3D data and comparison to observations we find evidence for both wave and non-wave mechanisms contributing to the EUV wave signal. We conclude with a comprehensive observation and modeling analysis of the 2010 June 13 EUV wave event, which was observed by the

Charge carrier recombination dynamics in perovskite and polymer solar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paulke, Andreas; Kniepert, Juliane; Kurpiers, Jona

2016-03-14

Time-delayed collection field experiments are applied to planar organometal halide perovskite (CH{sub 3}NH{sub 3}PbI{sub 3}) based solar cells to investigate charge carrier recombination in a fully working solar cell at the nanosecond to microsecond time scale. Recombination of mobile (extractable) charges is shown to follow second-order recombination dynamics for all fluences and time scales tested. Most importantly, the bimolecular recombination coefficient is found to be time-dependent, with an initial value of ca. 10{sup −9} cm{sup 3}/s and a progressive reduction within the first tens of nanoseconds. Comparison to the prototypical organic bulk heterojunction device PTB7:PC{sub 71}BM yields important differences with regardmore » to the mechanism and time scale of free carrier recombination.« less

Brayton cycle solarized advanced gas turbine

NASA Technical Reports Server (NTRS)

1986-01-01

Described is the development of a Brayton Engine/Generator Set for solar thermal to electrical power conversion, authorized under DOE/NASA Contract DEN3-181. The objective was to design, fabricate, assemble, and test a small, hybrid, 20-kW Brayton-engine-powered generator set. The latter, called a power conversion assembly (PCA), is designed to operate with solar energy obtained from a parobolic dish concentrator, 11 meters in diameter, or with fossil energy supplied by burning fuels in a combustor, or by a combination of both (hybrid model). The CPA consists of the Brayton cycle engine, a solar collector, a belt-driven 20-kW generator, and the necessary control systems for automatic operation in solar-only, fuel-only, and hybrid modes to supply electrical power to a utility grid. The original configuration of the generator set used the GTEC Model GTP36-51 gas turbine engine for the PCA prime mover. However, subsequent development of the GTEC Model AGT101 led to its selection as the powersource for the PCA. Performance characteristics of the latter, thermally coupled to a solar collector for operation in the solar mode, are presented. The PCA was successfully demonstrated in the fuel-only mode at the GTEC Phoenix, Arizona, facilities prior to its shipment to Sandia National Laboratory in Albuquerque, New Mexico, for installation and testing on a test bed concentractor (parabolic dish). Considerations relative to Brayton-engine development using the all-ceramic AGT101 when it becomes available, which would satisfy the DOE heat engine efficiency goal of 35 to 41 percent, are also discussed in the report.

Dynamic Seals for Advanced Hydraulic Systems

DTIC Science & Technology

1981-08-01

AFWAL-TR-81-.2066 t DYNAMIC SEALS FOR ADVANCED HYDRAULIC SYSTEMS cb- Robert S. Olsen I Vought Corporation P.O. Box 225907 Dallas, Texas 75265 August...Aeronautical Laboratories Air Force Systems Command 41 Wright-Patterson Air Force Base, Ohio 45433 82 Q L * a G ’ - -"o OW NOTICE When Government...and is approved for Publication. BRUC&- PBELL • •RICHARD D. FRANKLIN, MAJOR, USAF I Power Systems Branch -Chief, Power Systems Branch Aerospace Power

Mesospheric Dynamical Changes Induced by the Solar Proton Events in October-November 2003

NASA Technical Reports Server (NTRS)

Jackman, Charles H.; Roble, Raymond G.; Fleming, Eric L.

2007-01-01

The very large solar storms in October-November 2003 caused solar proton events (SPEs) at the Earth that impacted the upper atmospheric polar cap regions. The Thermosphere Ionosphere Mesosphere Electrodynamic General Circulation Model (TIME-GCM) was used to study the atmospheric dynamical influence of the solar protons that occurred in Oct-Nov 2003, the fourth largest period of SPEs measured in the past 40 years. The highly energetic solar protons caused ionization, as well as dissociation processes, and ultimately produced odd hydrogen (HOx) and odd nitrogen (NOy). Significant short-lived ozone decreases (10-70%) followed these enhancements of HOx and NOy and led to a cooling of most of the lower mesosphere. This cooling caused an atmospheric circulation change that led to adiabatic heating of the upper mesosphere. Temperature changes up to plus or minus 2.6 K were computed as well as wind (zonal, meridional, vertical) perturbations up to 20-25% of the background winds as a result of 22 the solar protons. The solar proton-induced mesospheric temperature and wind perturbations diminished over a period of 4-6 weeks after the SPEs. The Joule heating in the mesosphere, induced by the solar protons, was computed to be relatively insignificant for these solar storms with most of the temperature and circulation perturbations caused by ozone depletion in the sunlit hemisphere.

The effect of the low Earth orbit environment on space solar cells: Results of the Advanced Photovoltaic Experiment (S0014)

NASA Technical Reports Server (NTRS)

Brinker, David J.; Hickey, John R.; Scheiman, David A.

1993-01-01

The results of post-flight performance testing of the solar cells flown on the Advanced Photovoltaic Experiment are reported. Comparison of post-flight current-voltage characteristics with similar pre-flight data revealed little or no change in solar cell conversion efficiency, confirming the reliability and endurance of space photovoltaic cells. This finding is in agreement with the lack of significant physical changes in the solar cells despite nearly six years in the low Earth orbit environment.

High Current ESD Test of Advanced Triple Junction Solar Array Coupon

NASA Technical Reports Server (NTRS)

Wright, Kenneth H., Jr.; Schneider, Todd A.; Vaughn, Jason A.; Hoang, Bao; Wong, Frankie

2014-01-01

Testing was conducted on an Advanced Triple Junction (ATJ) coupon that was part of a risk reduction effort in the development of a high-powered solar array design by Space Systems Loral, LLC (SSL). The ATJ coupon was a small, 4-cell, two-string configuration of flight-type design that has served as the basic test coupon design used in previous SSL environmental aging campaigns. The objective of the present test was to evaluate the performance of the coupon after being subjected to induced electrostatic discharge (ESD) testing at two string voltages (100 V, 150 V) and four string currents (1.65 A, 2.0 A, 2.475 A, and 3.3 A). An ESD test circuit, unique to SSL solar array design, was built that simulates the effect of missing cells and strings in a full solar panel with special primary arc flashover circuitry. A total of 73 primary arcs were obtained that included 7 temporary sustained arcs (TSA) events. The durations of the TSAs ranged from 50 micro-seconds to 2.75 milli-seconds. All TSAs occurred at a string voltage of 150 V. Post-ESD functional testing showed that no degradation occurred due to the TSA events. These test results point to a robust design for application to a high-current, high-power mission.

[Advances in microbial solar cells--A review].

PubMed

Guo, Xiaoyun; Yu, Changping; Zheng, Tianling

2015-08-04

The energy crisis has become one of the major problems hindering the development of the world. The emergence of microbial fuel cells provides a new solution to the energy crisis. Microbial solar cells, integrating photosynthetic organisms such as plants and microalgae into microbial fuel cells, can convert solar energy into electrical energy. Microbial solar cell has steady electric energy, and broad application prospects in wastewater treatment, biodiesel processing and intermediate metabolites production. Here we reviewed recent progress of microbial solar cells from the perspective of the role of photosynthetic organisms in microbial fuel cells, based on a vast amount of literature, and discussed their advantages and deficiency. At last, brief analysis of the facing problems and research needs of microbial fuel cells are undertaken. This work was expected to be beneficial for the application of the microbial solar cells technology.

The Focusing Optics X-ray Solar Imager (FOXSI) sounding rocket, first flight

NASA Astrophysics Data System (ADS)

Christe, Steven; Glesener, L.; Ishikawa, S.; Ramsey, B.; Takahashi, T.; Watanabe, S.; Saito, S.; Lin, R. P.; Krucker, S.

2013-07-01

Understanding electron acceleration in solar flares requires X-ray studies with greater sensitivity and dynamic range than are available with current solar hard X-ray observers (i.e. the RHESSI spacecraft). RHESSI employs an indirect Fourier imaging method that is intrinsically limited in dynamic range and therefore can rarely image faint coronal flare sources in the presence of bright footpoints. With greater sensitivity and dynamic range, electron acceleration sites in the corona could be studied in great detail. Both these capabilities can be advanced by the use of direct focusing optics. The recently flown Focusing Optics X-ray Solar Imager (FOXSI) sounding rocket payload demonstrates the feasibility and usefulness of hard X-ray focusing optics for observations of solar hard X-rays. FOXSI features grazing-incidence replicated nickel optics made by the NASA Marshall Space Flight Center and fine-pitch silicon strip detectors developed by the Astro-H team at JAXA/ISAS. FOXSI flew successfully on November 2, 2012, producing images and spectra of a microflare and performing a search for nonthermal emission (4-15 keV) from nanoflares in the quiet Sun. Nanoflares are a candidate for providing the required energy to heat the solar corona to its high temperature of a few million degrees. A future satellite version of FOXSI, featuring similar optics and detectors, could make detailed observations of hard X-rays from flare-accelerated electrons, identifying and characterizing particle acceleration sites and mapping out paths of energetic electrons as they leave these sites and propagate throughout the solar corona.Abstract (2,250 Maximum Characters): Understanding electron acceleration in solar flares requires X-ray studies with greater sensitivity and dynamic range than are available with current solar hard X-ray observers (i.e. the RHESSI spacecraft). RHESSI employs an indirect Fourier imaging method that is intrinsically limited in dynamic range and therefore can

Solar photoassisted advanced oxidation process of azo dyes.

PubMed

Prato-Garcia, D; Buitrón, G

2009-01-01

Advanced oxidation processes assisted with natural solar radiation in CPC type reactors (parabolic collector compound), was applied for the degradation of three azo dyes: acid orange (AO7), acid red 151 (AR151) and acid blue 113 (AB113). Fenton, Fenton like and ferrioxalate-type complexes showed to be effective for degrade the azo linkage and moieties in different extensions. Initially, the best dose of reagents (Fe(3 + )-H(2)O(2)) was determined through a factorial experimental design, next, using response surface methodologies, the reagent consumption was reduced up to 40%, maintaining in all cases high decolourisation percentages (>98%) after 60 min. of phototreatment. In this work, it was also studied the effect of concentration changes of the influent between 100-300 mg/L and the operation of the photocatalytic process near neutral conditions (pH 6.0-6.5) by using ferrioxalate type complex (FeOx).

High Current ESD Test of Advanced Triple Junction Solar Array Coupon

NASA Technical Reports Server (NTRS)

Wright, Kenneth H., Jr.; Schneider, Todd A.; Vaughn, Jason A.; Hoang, Bao; Wong, Frankie

2014-01-01

Testing was conducted on an Advanced Triple Junction (ATJ) coupon that was part of a risk reduction effort in the development of a high-powered solar array design by Space Systems/Loral, LLC (SSL). The ATJ coupon was a small, 4-cell, two-string configuration that has served as the basic test coupon design used in previous SSL environmental aging campaigns. The coupon has many attributes of the flight design; e.g., substrate structure with graphite face sheets, integrated by-pass diodes, cell interconnects, RTV grout, wire routing, etc. The objective of the present test was to evaluate the performance of the coupon after being subjected to induced electrostatic discharge (ESD) testing at two string voltages (100 V, 150 V) and four array currents (1.65 A, 2.0 A, 2.475 A, and 3.3 A). An ESD test circuit, unique to SSL solar array design, was built that simulates the effect of missing cells and strings in a full solar panel with special primary arc flashover circuitry. A total of 73 primary arcs were obtained that included 7 temporary sustained arcs (TSA) events. The durations of the TSAs ranged from 50 micro-seconds to 2.75 milli-seconds. All TSAs occurred at a string voltage of 150 V. Post-test Large Area Pulsed Solar Simulator (LAPSS), Dark I-V, and By-Pass Diode tests showed that no degradation occurred due to the TSA events. In addition, the post-test insulation resistance measured was > 50 G-ohms between cells and substrate. These test results indicate a robust design for application to a high-current, high-power mission.

The Solar Dynamics Observatory: Your Eye On The Sun

NASA Technical Reports Server (NTRS)

Pesnell, William Dean

2008-01-01

The Sun hiccups and satellites die. That is what NASA's Living With a Star Program is all about. The Solar Dynamics Observatory (SDO) is the first Space Weather Mission in LWS. SDO's main goal is to understand, driving towards a predictive capability, those solar variations that influence life on Earth and humanity's technological systems. The past decade has seen an increasing emphasis on understanding the entire Sun, from the nuclear reactions at the core to the development and loss of magnetic loops in the corona. SDO's three science investigations (HMI, AIA, and EVE) will determine how the Sun's magnetic field is generated and structured, how this stored magnetic energy is released into the heliosphere and geospace as the solar wind, energetic particles, and variations in the solar irradiance. SDO will return full-disk Dopplergrams, full-disk vector magnetograms, full-disk images at nine E/UV wavelengths, and EUV spectral irradiances, all taken at a rapid cadence. This means you can "observe the database" to study events, but we can also move forward in producing quantitative models of what the Sun is doing today. SDO is scheduled to launch in 2008 on an Atlas V rocket from the Kennedy Space Center, Cape Canaveral, Florida. The satellite will fly in a 28 degree inclined geosynchronous orbit about the longitude of New Mexico, where a dedicated Ka-band ground station will receive the 150 Mbps data flow. How SDO data will transform the study of the Sun and its affect on Space Weather studies will be discussed.

Lower thermosphere (80-100 km) dynamics response to solar and geomagnetic activity: Overview

NASA Technical Reports Server (NTRS)

Kazimirovsky, E. S.

1989-01-01

The variations of solar and geomagnetic activity may affect the thermosphere circulation via plasma heating and electric fields, especially at high latitudes. The possibility exists that the energy involved in auroral and magnetic storms can produce significant changes of mesosphere and lower thermosphere wind systems. A study of global radar measurements of winds at 80 to 100 km region revealed the short term effects (correlation between wind field and geomagnetic storms) and long term variations over a solar cycle. It seems likely that the correlation results from a modification of planetary waves and tides propagated from below, thus altering the dynamical regime of the thermosphere. Sometimes the long term behavior points rather to a climatic variation with the internal atmospheric cause than to a direct solar control.

Solar-Iss a New Solar Reference Spectrum Covering the Far UV to the Infrared (165 to 3088 Nm) Based on Reanalyzed Solar/solspec Cycle 24 Observations

NASA Astrophysics Data System (ADS)

Damé, L.; Meftah, M.; Irbah, A.; Hauchecorne, A.; Bekki, S.; Bolsée, D.; Pereira, N.; Sluse, D.; Cessateur, G.

2017-12-01

Since April 5, 2008 and until February 15, 2017, the SOLSPEC (SOLar SPECtrometer) spectro-radiometer of the SOLAR facility on the International Space Station performed accurate measurements of Solar Spectral Irradiance (SSI) from the far ultraviolet to the infrared (165 nm to 3088 nm). These measurements, unique by their large spectral coverage and long time range, are of primary importance for a better understanding of solar physics and of the impact of solar variability on climate (via Earth's atmospheric photochemistry), noticeably through the "top-down" mechanism amplifying ultraviolet (UV) solar forcing effects on the climate (UV affects stratospheric dynamics and temperatures, altering interplanetary waves and weather patterns both poleward and downward to the lower stratosphere and troposphere regions). SOLAR/SOLSPEC, with almost 9 years of observations covering the essential of the unusual solar cycle 24 from minimum in 2008 to maximum, allowed to establish new reference solar spectra from UV to IR (165 to 3088 nm) at minimum (beginning of mission) and maximum of activity. The complete reanalysis was possible thanks to revised engineering corrections, improved calibrations and advanced procedures to account for thermal, aging and pointing corrections. The high quality and sensitivity of SOLSPEC data allow to follow temporal variability in UV but also in visible along the cycle. Uncertainties on these measurements are evaluated and results, absolute reference spectra and variability, are compared with other measurements (WHI, ATLAS-3, SCIAMACHY, SORCE/SOLSTICE, SORCE/SIM) and models (SATIRE-S, NRLSSI, NESSY)

Overview of the solar dynamic ground test demonstration program

NASA Technical Reports Server (NTRS)

Shaltens, Richard K.; Boyle, Robert V.

1993-01-01

The Solar Dynamic (SD) Ground Test Demonstration (GTD) program demonstrates the availability of SD technologies in a simulated space environment at the NASA Lewis Research Center (LeRC) vacuum facility. An aerospace industry/ government team is working together to design, fabricate, build, and test a complete SD system. This paper reviews the goals and status of the SD GTD program. A description of the SD system includes key design features of the system, subsystems, and components as reported at the Critical Design Review (CDR).

Solar thematic maps for space weather operations

USGS Publications Warehouse

Rigler, E. Joshua; Hill, Steven M.; Reinard, Alysha A.; Steenburgh, Robert A.

2012-01-01

Thematic maps are arrays of labels, or "themes", associated with discrete locations in space and time. Borrowing heavily from the terrestrial remote sensing discipline, a numerical technique based on Bayes' theorem captures operational expertise in the form of trained theme statistics, then uses this to automatically assign labels to solar image pixels. Ultimately, regular thematic maps of the solar corona will be generated from high-cadence, high-resolution SUVI images, the solar ultraviolet imager slated to fly on NOAA's next-generation GOES-R series of satellites starting ~2016. These thematic maps will not only provide quicker, more consistent synoptic views of the sun for space weather forecasters, but digital thematic pixel masks (e.g., coronal hole, active region, flare, etc.), necessary for a new generation of operational solar data products, will be generated. This paper presents the mathematical underpinnings of our thematic mapper, as well as some practical algorithmic considerations. Then, using images from the Solar Dynamics Observatory (SDO) Advanced Imaging Array (AIA) as test data, it presents results from validation experiments designed to ascertain the robustness of the technique with respect to differing expert opinions and changing solar conditions.

Analysis Of Dynamic Interactions Between Solar Array Simulators And Spacecraft Power Conditioning And Distribution Units

NASA Astrophysics Data System (ADS)

Valdivia, V.; Barrado, A.; Lazaro, A.; Rueda, P.; Tonicello, F.; Fernandez, A.; Mourra, O.

2011-10-01

Solar array simulators (SASs) are hardware devices, commonly applied instead of actual solar arrays (SAs) during the design process of spacecrafts power conditioning and distribution units (PCDUs), and during spacecrafts assembly integration and tests. However, the dynamic responses between SASs and actual SAs are usually different. This fact plays an important role, since the dynamic response of the SAS may influence significantly the dynamic behaviour of the PCDU under certain conditions, even leading to instability. This paper deals with the dynamic interactions between SASs and PCDUs. Several methods for dynamic characterization of the SASs are discussed, and the response of commercial SASs widely applied in the space industry is compared to that of actual SAs. After that, the interactions are experimentally analyzed by using a boost converter connected to the aforementioned SASs, thus demonstrating their critical importance. The interactions are first tackled analytically by means of small-signal models, and finally a black-box modelling method of SASs is proposed as a useful tool to analyze the interactions by means of simulation. The capabilities of both the analytical method and the black- box model to predict the interactions are demonstrated.

Intermittent Reconnection and Plasmoids in UV Bursts in the Low Solar Atmosphere

NASA Astrophysics Data System (ADS)

Rouppe van der Voort, L.; De Pontieu, B.; Scharmer, G. B.; de la Cruz Rodríguez, J.; Martínez-Sykora, J.; Nóbrega-Siverio, D.; Guo, L. J.; Jafarzadeh, S.; Pereira, T. M. D.; Hansteen, V. H.; Carlsson, M.; Vissers, G.

2017-12-01

Magnetic reconnection is thought to drive a wide variety of dynamic phenomena in the solar atmosphere. Yet, the detailed physical mechanisms driving reconnection are difficult to discern in the remote sensing observations that are used to study the solar atmosphere. In this Letter, we exploit the high-resolution instruments Interface Region Imaging Spectrograph and the new CHROMIS Fabry-Pérot instrument at the Swedish 1-m Solar Telescope (SST) to identify the intermittency of magnetic reconnection and its association with the formation of plasmoids in so-called UV bursts in the low solar atmosphere. The Si IV 1403 Å UV burst spectra from the transition region show evidence of highly broadened line profiles with often non-Gaussian and triangular shapes, in addition to signatures of bidirectional flows. Such profiles had previously been linked, in idealized numerical simulations, to magnetic reconnection driven by the plasmoid instability. Simultaneous CHROMIS images in the chromospheric Ca II K 3934 Å line now provide compelling evidence for the presence of plasmoids by revealing highly dynamic and rapidly moving brightenings that are smaller than 0.″2 and that evolve on timescales of the order of seconds. Our interpretation of the observations is supported by detailed comparisons with synthetic observables from advanced numerical simulations of magnetic reconnection and associated plasmoids in the chromosphere. Our results highlight how subarcsecond imaging spectroscopy sensitive to a wide range of temperatures combined with advanced numerical simulations that are realistic enough to compare with observations can directly reveal the small-scale physical processes that drive the wide range of phenomena in the solar atmosphere.

Advancements of the Lightweight Integrated Solar Array and Transceiver (LISA-T) Small Spacecraft System

NASA Technical Reports Server (NTRS)

Lockett, Tiffany Russell; Martinez, Armando; Boyd, Darren; SanSouice, Michael; Farmer, Brandon; Schneider, Todd; Laue, Greg; Fabisinski, Leo; Johnson, Les; Carr, John A.

2015-01-01

This paper describes recent advancements of the Lightweight Integrated Solar Array and Transceiver (LISA-T) currently being developed at NASA's Marshall Space Flight Center. The LISA-T array comprises a launch stowed, orbit deployed structure on which thin-film photovoltaic (PV) and antenna devices are embedded. The system provides significant electrical power generation at low weights, high stowage efficiency, and without the need for solar tracking. Leveraging high-volume terrestrial-market PVs also gives the potential for lower array costs. LISA-T is addressing the power starvation epidemic currently seen by many small-scale satellites while also enabling the application of deployable antenna arrays. Herein, an overview of the system and its applications are presented alongside sub-system development progress and environmental testing plans.

Advancements of the Lightweight Integrated Solar Array and Transceiver (LISA-T) Small Spacecraft System

NASA Technical Reports Server (NTRS)

Russell, Tiffany; Martinez, Armando; Boyd, Darren; SanSoucie, Michael; Farmer, Brandon; Schneider, Todd; Fabisinski, Leo; Johnson, Les; Carr, John A.

2015-01-01

This paper describes recent advancements of the Lightweight Integrated Solar Array and Transceiver (LISA-T) currently being developed at NASA's Marshall Space Flight Center. The LISA-T array comprises a launch stowed, orbit deployed structure on which thin-film photovoltaic (PV) and antenna devices are embedded. The system provides significant electrical power generation at low weights, high stowage efficiency, and without the need for solar tracking. Leveraging high-volume terrestrial-market PVs also gives the potential for lower array costs. LISA-T is addressing the power starvation epidemic currently seen by many small-scale satellites while also enabling the application of deployable antenna arrays. Herein, an overview of the system and its applications are presented alongside sub-system development progress and environmental testing plans/initial results.

Ground test program for a full-size solar dynamic heat receiver

NASA Technical Reports Server (NTRS)

Sedgwick, L. M.; Kaufmann, K. J.; Mclallin, K. L.; Kerslake, T. W.

1991-01-01

Test hardware, facilities, and procedures were developed to conduct ground testing of a full-size, solar dynamic heat receiver in a partially simulated, low earth orbit environment. The heat receiver was designed to supply 102 kW of thermal energy to a helium and xenon gas mixture continuously over a 94 minute orbit, including up to 36 minutes of eclipse. The purpose of the test program was to quantify the receiver thermodynamic performance, its operating temperatures, and thermal response to changes in environmental and power module interface boundary conditions. The heat receiver was tested in a vacuum chamber using liquid nitrogen cold shrouds and an aperture cold plate. Special test equipment was designed to provide the required ranges in interface boundary conditions that typify those expected or required for operation as part of the solar dynamic power module on the Space Station Freedom. The support hardware includes an infrared quartz lamp heater with 30 independently controllable zones and a closed-Brayton cycle engine simulator to circulate and condition the helium-xenon gas mixture. The test article, test support hardware, facilities, and instrumentation developed to conduct the ground test program are all described.

Ground test program for a full-size solar dynamic heat receiver

NASA Technical Reports Server (NTRS)

Sedgwick, L. M.; Kaufmann, K. J.; Mclallin, K. L.; Kerslake, T. W.

1991-01-01

Test hardware, facilities, and procedures were developed to conduct ground testing of a full size, solar dynamic heat receiver in a partially simulated, low Earth orbit environment. The heat receiver was designed to supply 102 kW of thermal energy to a helium and xenon gas mixture continuously over a 94 minute orbit, including up to 36 minutes of eclipse. The purpose of the test program was to quantify the receiver thermodynamic performance, its operating temperatures, and thermal response to changes in environmental and power module interface boundary conditions. The heat receiver was tested in a vacuum chamber using liquid nitrogen cold shrouds and an aperture cold plate. Special test equipment were designed to provide the required ranges in interface boundary conditions that typify those expected or required for operation as part of the solar dynamic power module on the Space Station Freedom. The support hardware includes an infrared quartz lamp heater with 30 independently controllable zones and a closed Brayton cycle engine simulator to circulate and condition the helium xenon gas mixture. The test article, test support hardware, facilities, and instrumentation developed to conduct the ground test program are all described.

Ground test program for a full-size solar dynamic heat receiver

NASA Astrophysics Data System (ADS)

Sedgwick, L. M.; Kaufmann, K. J.; McLallin, K. L.; Kerslake, T. W.

Test hardware, facilities, and procedures were developed to conduct ground testing of a full-size, solar dynamic heat receiver in a partially simulated, low earth orbit environment. The heat receiver was designed to supply 102 kW of thermal energy to a helium and xenon gas mixture continuously over a 94 minute orbit, including up to 36 minutes of eclipse. The purpose of the test program was to quantify the receiver thermodynamic performance, its operating temperatures, and thermal response to changes in environmental and power module interface boundary conditions. The heat receiver was tested in a vacuum chamber using liquid nitrogen cold shrouds and an aperture cold plate. Special test equipment was designed to provide the required ranges in interface boundary conditions that typify those expected or required for operation as part of the solar dynamic power module on the Space Station Freedom. The support hardware includes an infrared quartz lamp heater with 30 independently controllable zones and a closed-Brayton cycle engine simulator to circulate and condition the helium-xenon gas mixture. The test article, test support hardware, facilities, and instrumentation developed to conduct the ground test program are all described.

Ionospheric Scintillation Induced by Solar Wind Dynamic Pressure Enhancements in the Southern Hemisphere

NASA Astrophysics Data System (ADS)

Coppeans, T.; Zou, S.; Weatherwax, A. T.; Coster, A. J.

2017-12-01

Ionospheric scintillation is the random fluctuation in GPS signal radio waves passing through the ionosphere, a phenomenon that can result in the loss of GPS tracking, but can also reveal information about plasma structures in the ionosphere. Sudden compression of the Earth's magnetosphere by a solar wind dynamic pressure enhancement can cause dramatic changes in the E and F region ionospheric plasma. In this study, we investigate the possible ionospheric scintillation induced by solar wind pressure enhancements using ground-based scintillation receivers located at the McMurdo station and the South Pole station in Antarctica. Various studies of scintillation effects have been carried out, mainly in the northern hemisphere, while the southern hemisphere remains less studied. A pool of storm sudden commencements occurring between Jan. 2011 and Dec. 2014 were sorted based on solar wind dynamic pressure enhancement, background conditions, availability of data, and magnitude of scintillation response. Among the 89 events examined, 14 of them exhibited enhanced scintillation and were selected for detailed examination. Besides the scintillation receivers, other datasets have also been used to carry out the above study, including field-aligned currents from AMPERE, and global GPS TEC. Effects of FACs and TEC/TEC gradients on the generation of these scintillations are studied.

The Coronal Solar Magnetism Observatory

NASA Astrophysics Data System (ADS)

Tomczyk, S.; Landi, E.; Zhang, J.; Lin, H.; DeLuca, E. E.

2015-12-01

Measurements of coronal and chromospheric magnetic fields are arguably the most important observables required for advances in our understanding of the processes responsible for coronal heating, coronal dynamics and the generation of space weather that affects communications, GPS systems, space flight, and power transmission. The Coronal Solar Magnetism Observatory (COSMO) is a proposed ground-based suite of instruments designed for routine study of coronal and chromospheric magnetic fields and their environment, and to understand the formation of coronal mass ejections (CME) and their relation to other forms of solar activity. This new facility will be operated by the High Altitude Observatory of the National Center for Atmospheric Research (HAO/NCAR) with partners at the University of Michigan, the University of Hawaii and George Mason University in support of the solar and heliospheric community. It will replace the current NCAR Mauna Loa Solar Observatory (http://mlso.hao.ucar.edu). COSMO will enhance the value of existing and new observatories on the ground and in space by providing unique and crucial observations of the global coronal and chromospheric magnetic field and its evolution. The design and current status of the COSMO will be reviewed.

Automated detection of solar eruptions

NASA Astrophysics Data System (ADS)

Hurlburt, N.

2015-12-01

Observation of the solar atmosphere reveals a wide range of motions, from small scale jets and spicules to global-scale coronal mass ejections (CMEs). Identifying and characterizing these motions are essential to advancing our understanding of the drivers of space weather. Both automated and visual identifications are currently used in identifying Coronal Mass Ejections. To date, eruptions near the solar surface, which may be precursors to CMEs, have been identified primarily by visual inspection. Here we report on Eruption Patrol (EP): a software module that is designed to automatically identify eruptions from data collected by the Atmospheric Imaging Assembly on the Solar Dynamics Observatory (SDO/AIA). We describe the method underlying the module and compare its results to previous identifications found in the Heliophysics Event Knowledgebase. EP identifies eruptions events that are consistent with those found by human annotations, but in a significantly more consistent and quantitative manner. Eruptions are found to be distributed within 15 Mm of the solar surface. They possess peak speeds ranging from 4 to 100 km/s and display a power-law probability distribution over that range. These characteristics are consistent with previous observations of prominences.

Porous media fracturing dynamics: stepwise crack advancement and fluid pressure oscillations

NASA Astrophysics Data System (ADS)

Cao, Toan D.; Hussain, Fazle; Schrefler, Bernhard A.

2018-02-01

We present new results explaining why fracturing in saturated porous media is not smooth and continuous but is a distinct stepwise process concomitant with fluid pressure oscillations. All exact solutions and almost all numerical models yield smooth fracture advancement and fluid pressure evolution, while recent experimental results, mainly from the oil industry, observation from geophysics and a very few numerical results for the quasi-static case indeed reveal the stepwise phenomenon. We summarize first these new experiments and these few numerical solutions for the quasi-static case. Both mechanical loading and pressure driven fractures are considered because their behaviours differ in the direction of the pressure jumps. Then we explore stepwise crack tip advancement and pressure fluctuations in dynamic fracturing with a hydro-mechanical model of porous media based on the Hybrid Mixture Theory. Full dynamic analyses of examples dealing with both hydraulic fracturing and mechanical loading are presented. The stepwise fracture advancement is confirmed in the dynamic setting as well as in the pressure fluctuations, but there are substantial differences in the frequency contents of the pressure waves in the two loading cases. Comparison between the quasi-static and fully dynamic solutions reveals that the dynamic response gives much more information such as the type of pressure oscillations and related frequencies and should be applied whenever there is a doubt about inertia forces playing a role - the case in most fracturing events. In the absence of direct relevant dynamic tests on saturated media some experimental results on dynamic fracture in dry materials, a fast hydraulic fracturing test and observations from geophysics confirm qualitatively the obtained results such as the type of pressure oscillations and the substantial difference in the behaviour under the two loading cases.

The solar probe and coronal dynamics

NASA Technical Reports Server (NTRS)

Belcher, J.; Heinemann, M.; Goodrich, C.

1978-01-01

The discovery of coronal holes led to basic changes in ideas about the structure of the low corona and its expansion into the solar wind. The nature of the energy flux is not understood. Current ideas include enhanced thermal conductivities, extended MHD wave heating, and wave momentum transfer, all in rapidly diverging geometries. There is little feel for the relative importance of these processes. The Solar Probe, with its penetration deep into the solar corona, could lead to observational constraints on their relative importance, and thus to an understanding of the origin of the solar wind. Observations from the Solar Probe will also bear on such questions as to whether small scale "intrastream" structure is common close to the Sun in open field-line regions, whether the properties of the wind are pronouncedly different over closed and open field-line regions at five solar radii, and many others. The resolution of these questions requires measurements of the magnetic field and of the proton and electron distribution functions.

Ion measurements during Pioneer Venus reentry: Implications for solar cycle variation of ion composition and dynamics

NASA Technical Reports Server (NTRS)

Grebowsky, J. M.; Hartle, R. E.; Kar, J.; Cloutier, P. A.; Taylor, H. A., Jr.; Brace, L. H.

1993-01-01

During the final, low solar activity phase of the Pioneer Venus (PV) mission, the Orbiter Ion Mass Spectrometer (OIMS) measurements found all ion species, in the midnight-dusk sector, reduced in concentration relative to that observed at solar maximum. Molecular ion species comprised a greater part of the total ion concentration as O(+) and H(+) had the greatest depletions. The nightside ionospheric states were strikingly similar to the isolated solar maximum 'disappearing' ionospheres. Both are very dynamic states characterized by a rapidly drifting plasma and 30-100 eV superthermal O(+) ions.

Advanced Solar-propelled Cargo Spacecraft for Mars Missions

NASA Technical Reports Server (NTRS)

Auziasdeturenne, Jacqueline; Beall, Mark; Burianek, Joseph; Cinniger, Anna; Dunmire, Barbrina; Haberman, Eric; Iwamoto, James; Johnson, Stephen; Mccracken, Shawn; Miller, Melanie

1989-01-01

Three concepts for an unmanned, solar powered, cargo spacecraft for Mars support missions were investigated. These spacecraft are designed to carry a 50,000 kg payload from a low Earth orbit to a low Mars orbit. Each design uses a distinctly different propulsion system: A Solar Radiation Absorption (SRA) system, a Solar-Pumped Laser (SPL) system and a solar powered magnetoplasmadynamic (MPD) arc system. The SRA directly converts solar energy to thermal energy in the propellant through a novel process. In the SPL system, a pair of solar-pumped, multi-megawatt, CO2 lasers in sunsynchronous Earth orbit converts solar energy to laser energy. The MPD system used indium phosphide solar cells to convert sunlight to electricity, which powers the propulsion system. Various orbital transfer options are examined for these concepts. In the SRA system, the mother ship transfers the payload into a very high Earth orbit and a small auxiliary propulsion system boosts the payload into a Hohmann transfer to Mars. The SPL spacecraft and the SPL powered spacecraft return to Earth for subsequent missions. The MPD propelled spacecraft, however, remains at Mars as an orbiting space station. A patched conic approximation was used to determine a heliocentric interplanetary transfer orbit for the MPD propelled spacecraft. All three solar-powered spacecraft use an aerobrake procedure to place the payload into a low Mars parking orbit. The payload delivery times range from 160 days to 873 days (2.39 years).

Systems and methods for advanced ultra-high-performance InP solar cells

DOEpatents

Wanlass, Mark

2017-03-07

Systems and Methods for Advanced Ultra-High-Performance InP Solar Cells are provided. In one embodiment, an InP photovoltaic device comprises: a p-n junction absorber layer comprising at least one InP layer; a front surface confinement layer; and a back surface confinement layer; wherein either the front surface confinement layer or the back surface confinement layer forms part of a High-Low (HL) doping architecture; and wherein either the front surface confinement layer or the back surface confinement layer forms part of a heterointerface system architecture.

The effects of regional insolation differences upon advanced solar thermal electric power plant performance and energy costs

NASA Technical Reports Server (NTRS)

Latta, A. F.; Bowyer, J. M.; Fujita, T.; Richter, P. H.

1980-01-01

The performance and cost of four 10 MWe advanced solar thermal electric power plants sited in various regions of the continental United States was studied. Each region has different insolation characteristics which result in varying collector field areas, plant performance, capital costs and energy costs. The regional variation in solar plant performance was assessed in relation to the expected rise in the future cost of residential and commercial electricity supplied by conventional utility power systems in the same regions. A discussion of the regional insolation data base is presented along with a description of the solar systems performance and costs. A range for the forecast cost of conventional electricity by region and nationally over the next several decades is given.

A PROPOSED PARADIGM FOR SOLAR CYCLE DYNAMICS MEDIATED VIA TURBULENT PUMPING OF MAGNETIC FLUX IN BABCOCK–LEIGHTON-TYPE SOLAR DYNAMOS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hazra, Soumitra; Nandy, Dibyendu

At present, the Babcock–Leighton flux transport solar dynamo models appear to be the most promising models for explaining diverse observational aspects of the sunspot cycle. The success of these flux transport dynamo models is largely dependent upon a single-cell meridional circulation with a deep equatorward component at the base of the Sun’s convection zone. However, recent observations suggest that the meridional flow may in fact be very shallow (confined to the top 10% of the Sun) and more complex than previously thought. Taken together, these observations raise serious concerns on the validity of the flux transport paradigm. By accounting formore » the turbulent pumping of magnetic flux, as evidenced in magnetohydrodynamic simulations of solar convection, we demonstrate that flux transport dynamo models can generate solar-like magnetic cycles even if the meridional flow is shallow. Solar-like periodic reversals are recovered even when meridional circulation is altogether absent. However, in this case, the solar surface magnetic field dynamics does not extend all the way to the polar regions. Very importantly, our results demonstrate that the Parker–Yoshimura sign rule for dynamo wave propagation can be circumvented in Babcock–Leighton dynamo models by the latitudinal component of turbulent pumping, which can generate equatorward propagating sunspot belts in the absence of a deep, equatorward meridional flow. We also show that variations in turbulent pumping coefficients can modulate the solar cycle amplitude and periodicity. Our results suggest the viability of an alternate magnetic flux transport paradigm—mediated via turbulent pumping—for sustaining solar-stellar dynamo action.« less

Modeling the Solar Convective Dynamo and Emerging Flux

NASA Astrophysics Data System (ADS)

Fan, Y.

2017-12-01

Significant advances have been made in recent years in global-scale fully dynamic three-dimensional convective dynamo simulations of the solar/stellar convective envelopes to reproduce some of the basic features of the Sun's large-scale cyclic magnetic field. It is found that the presence of the dynamo-generated magnetic fields plays an important role for the maintenance of the solar differential rotation, without which the differential rotation tends to become anti-solar (with a faster rotating pole instead of the observed faster rotation at the equator). Convective dynamo simulations are also found to produce emergence of coherent super-equipartition toroidal flux bundles with a statistically significant mean tilt angle that is consistent with the mean tilt of solar active regions. The emerging flux bundles are sheared by the giant cell convection into a forward leaning loop shape with its leading side (in the direction of rotation) pushed closer to the strong downflow lanes. Such asymmetric emerging flux pattern may lead to the observed asymmetric properties of solar active regions.

Fault Detection and Correction for the Solar Dynamics Observatory Attitude Control System

NASA Technical Reports Server (NTRS)

Starin, Scott R.; Vess, Melissa F.; Kenney, Thomas M.; Maldonado, Manuel D.; Morgenstern, Wendy M.

2007-01-01

The Solar Dynamics Observatory is an Explorer-class mission that will launch in early 2009. The spacecraft will operate in a geosynchronous orbit, sending data 24 hours a day to a devoted ground station in White Sands, New Mexico. It will carry a suite of instruments designed to observe the Sun in multiple wavelengths at unprecedented resolution. The Atmospheric Imaging Assembly includes four telescopes with focal plane CCDs that can image the full solar disk in four different visible wavelengths. The Extreme-ultraviolet Variability Experiment will collect time-correlated data on the activity of the Sun's corona. The Helioseismic and Magnetic Imager will enable study of pressure waves moving through the body of the Sun. The attitude control system on Solar Dynamics Observatory is responsible for four main phases of activity. The physical safety of the spacecraft after separation must be guaranteed. Fine attitude determination and control must be sufficient for instrument calibration maneuvers. The mission science mode requires 2-arcsecond control according to error signals provided by guide telescopes on the Atmospheric Imaging Assembly, one of the three instruments to be carried. Lastly, accurate execution of linear and angular momentum changes to the spacecraft must be provided for momentum management and orbit maintenance. In thsp aper, single-fault tolerant fault detection and correction of the Solar Dynamics Observatory attitude control system is described. The attitude control hardware suite for the mission is catalogued, with special attention to redundancy at the hardware level. Four reaction wheels are used where any three are satisfactory. Four pairs of redundant thrusters are employed for orbit change maneuvers and momentum management. Three two-axis gyroscopes provide full redundancy for rate sensing. A digital Sun sensor and two autonomous star trackers provide two-out-of-three redundancy for fine attitude determination. The use of software to maximize

Functional safety for the Advanced Technology Solar Telescope

NASA Astrophysics Data System (ADS)

Bulau, Scott; Williams, Timothy R.

2012-09-01

Since inception, the Advanced Technology Solar Telescope (ATST) has planned to implement a facility-wide functional safety system to protect personnel from harm and prevent damage to the facility or environment. The ATST will deploy an integrated safety-related control system (SRCS) to achieve functional safety throughout the facility rather than relying on individual facility subsystems to provide safety functions on an ad hoc basis. The Global Interlock System (GIS) is an independent, distributed, facility-wide, safety-related control system, comprised of commercial off-the-shelf (COTS) programmable controllers that monitor, evaluate, and control hazardous energy and conditions throughout the facility that arise during operation and maintenance. The GIS has been designed to utilize recent advances in technology for functional safety plus revised national and international standards that allow for a distributed architecture using programmable controllers over a local area network instead of traditional hard-wired safety functions, while providing an equivalent or even greater level of safety. Programmable controllers provide an ideal platform for controlling the often complex interrelationships between subsystems in a modern astronomical facility, such as the ATST. A large, complex hard-wired relay control system is no longer needed. This type of system also offers greater flexibility during development and integration in addition to providing for expanded capability into the future. The GIS features fault detection, self-diagnostics, and redundant communications that will lead to decreased maintenance time and increased availability of the facility.

Advanced vehicle dynamics of heavy trucks with the perspective of road safety

NASA Astrophysics Data System (ADS)

Trigell, Annika Stensson; Rothhämel, Malte; Pauwelussen, Joop; Kural, Karel

2017-10-01

This paper presents state-of-the art within advanced vehicle dynamics of heavy trucks with the perspective of road safety. The most common accidents with heavy trucks involved are truck against passenger cars. Safety critical situations are for example loss of control (such as rollover and lateral stability) and a majority of these occur during speed when cornering. Other critical situations are avoidance manoeuvre and road edge recovery. The dynamic behaviour of heavy trucks have significant differences compared to passenger cars and as a consequence, successful application of vehicle dynamic functions for enhanced safety of trucks might differ from the functions in passenger cars. Here, the differences between vehicle dynamics of heavy trucks and passenger cars are clarified. Advanced vehicle dynamics solutions with the perspective of road safety of trucks are presented, beginning with the topic vehicle stability, followed by the steering system, the braking system and driver assistance systems that differ in some way from that of passenger cars as well.

Thermal energy storage for a space solar dynamic power system

NASA Technical Reports Server (NTRS)

Faget, N. M.; Fraser, W. M., Jr.; Simon, W. E.

1985-01-01

In the past, NASA has employed solar photovoltaic devices for long-duration missions. Thus, the Skylab system has operated with a silicon photovoltaic array and a nickel-cadmium electrochemical system energy storage system. Difficulties regarding the employment of such a system for the larger power requirements of the Space Station are related to a low orbit system efficiency and the large weight of the battery. For this reason the employment of a solar dynamic power system (SDPS) has been considered. The primary components of an SDPS include a concentrating mirror, a heat receiver, a thermal energy storage (TES) system, a thermodynamic heat engine, an alternator, and a heat rejection system. The heat-engine types under consideration are a Brayton cycle engine, an organic Rankine cycle engine, and a free-piston/linear-alternator Stirling cycle engine. Attention is given to a system description, TES integration concepts, and a TES technology assessment.

Recent advances in visible-light-responsive photocatalysts for hydrogen production and solar energy conversion--from semiconducting TiO2 to MOF/PCP photocatalysts.

PubMed

Horiuchi, Yu; Toyao, Takashi; Takeuchi, Masato; Matsuoka, Masaya; Anpo, Masakazu

2013-08-28

The present perspective describes recent advances in visible-light-responsive photocatalysts intended to develop novel and efficient solar energy conversion technologies, including water splitting and photofuel cells. Water splitting is recognized as one of the most promising techniques to convert solar energy as a clean and abundant energy resource into chemical energy in the form of hydrogen. In recent years, increasing concern is directed to not only the development of new photocatalytic materials but also the importance of technologies to produce hydrogen and oxygen separately. Photofuel cells can convert solar energy into electrical energy by decomposing bio-related compounds and livestock waste as fuels. The advances of photocatalysts enabling these solar energy conversion technologies have been going on since the discovery of semiconducting titanium dioxide materials and have extended to organic-inorganic hybrid materials, such as metal-organic frameworks and porous coordination polymers (MOF/PCP).

Production of the 4.26 m ZERODUR mirror blank for the Advanced Technology Solar telescope (ATST)

NASA Astrophysics Data System (ADS)

Jedamzik, Ralf; Werner, Thomas; Westerhoff, Thomas

2014-07-01

The Daniel K. Inouye Solar Telescope (DKIST, formerly the Advanced Technology Solar Telescope, ATST) will be the most powerful solar telescope in the world. It is currently being built by the Association of Universities for Research in Astronomy (AURA) in a height of 3000 m above sea level on the mountain Haleakala of Maui, Hawaii. The primary mirror blank of diameter 4.26 m is made of the extremely low thermal expansion glass ceramic ZERODUR® of SCHOTT AG Advanced Optics. The DKIST primary mirror design is extremely challenging. With a mirror thickness of only 78 to 85 mm it is the smallest thickness ever machined on a mirror of 4.26 m in diameter. Additionally the glassy ZERODUR® casting is one of the largest in size ever produced for a 4 m class ZERODUR® mirror blank. The off axis aspherical mirror surface required sophisticated grinding procedures to achieve the specified geometrical tolerance. The small thickness of about 80 mm required special measures during processing, lifting and transport. Additionally acid etch treatment was applied to the convex back-surface and the conical shaped outer diameter surface to improve the strength of the blank. This paper reports on the challenging tasks and the achievements on the material property and dimensional specification parameter during the production of the 4.26 m ZERODUR® primary mirror blank for AURA.

X-class Solar Flare on March 29, 2014

NASA Image and Video Library

2014-03-31

Extreme ultraviolet light streams out of an X-class solar flare as seen in this image captured on March 29, 2014, by NASA's Solar Dynamics Observatory. This image blends two wavelengths of light: 304 and 171 Angstroms, which help scientists observe the lower levels of the sun's atmosphere. More info: The sun emitted a significant solar flare, peaking at 1:48 p.m. EDT March 29, 2014, and NASA's Solar Dynamics Observatory captured images of the event. Solar flares are powerful bursts of radiation. Harmful radiation from a flare cannot pass through Earth's atmosphere to physically affect humans on the ground, however -- when intense enough -- they can disturb the atmosphere in the layer where GPS and communications signals travel. To see how this event impacted Earth, please visit NOAA's Space Weather Prediction Center at spaceweather.gov, the U.S. government's official source for space weather forecasts, alerts, watches and warnings. This flare is classified as an X.1-class flare. X-class denotes the most intense flares, while the number provides more information about its strength. An X2 is twice as intense as an X1, an X3 is three times as intense, etc. Credit: NASA/SDO NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Multi-thermal observations of flares and eruptions with the Atmospheric Imaging Assembly on the Solar Dynamics Observatory. (Invited)

NASA Astrophysics Data System (ADS)

Schrijver, C. J.; Aia Science Team

2010-12-01

The revolutionary advance in observational capabilities offered by SDO's AIA offers new views of solar flares and eruptions. The high cadence and spatial resolution, the full-Sun coverage, and the variety of thermal responses of the AIA channels from thousands to millions of degrees enable the study the source regions of solar explosions, as well as the responses of the solar corona from their immediate vicinity to regions over a solar radius away. These observations emphasize the importance of magnetic connectivity and topology, the frequent occurrence of fast wave-like perturbations, and the contrasts between impulsive compact X-ray-bright flares and long-duration EUV-bright phenomena.

The Structure and Dynamics of the Solar Corona and Inner Heliosphere

NASA Technical Reports Server (NTRS)

Mikic, Zoran; Grebowsky, J. (Technical Monitor)

2001-01-01

This report covers technical progress during the third quarter of the second year of NASA Sun-Earth Connections Theory Program (SECTP) contract 'The Structure and Dynamics of the Solar Corona and Inner Heliosphere,' NAS5-99188, between NASA and Science Applications International Corporation, and covers the period February 16, 2001 to May 15, 2001. Under this contract SAIC and the University of California, Irvine (UCI) have conducted research into theoretical modeling of active regions, the solar corona, and the inner heliosphere, using the MHD model.In this report we summarize the accomplishments made by our group during the first seven quarters of our Sun-Earth Connection Theory Program contract. The descriptions are intended to illustrate our principal results. A full account can be found in the referenced publications.

Solar radiation variability over La Réunion island and associated larger-scale dynamics

NASA Astrophysics Data System (ADS)

Mialhe, Pauline; Morel, Béatrice; Pohl, Benjamin; Bessafi, Miloud; Chabriat, Jean-Pierre

2017-04-01

This study aims to examine the solar radiation variability over La Réunion island and its relationship with large-scale circulation. The Satellite Application Facility on Climate Monitoring (CM SAF) produces a Shortwave Incoming Solar radiation (SIS) data record called Solar surfAce RAdiation Heliosat - East (SARAH-E). A comparison to in situ observations from Météo-France measurements networks quantifies the skill of SARAH-E grids which we use as dataset. First step of the work, irradiance mean cycles are calculated to describe the diurnal-seasonal SIS behaviour over La Réunion island. By analogy with the climate anomalies, instantaneous deviations are computed after removal of the mean states. Finally, we associate these anomalies with larger-scale atmospheric dynamics into the South West Indian Ocean by applying multivariate clustering analyses (Hierarchical Ascending Classification, k-means).

Advanced Gun System (AGS) Dynamic Characterization: Modal Test and Analysis, High-Frequency Analysis.

DTIC Science & Technology

1999-12-01

frequency data (to 10 kHz) in the AGS test. 3.2 High-Frequency Damping Determination by Wavelet Transform. The continuous wavelet transform (CWT...ARMY RESEARCH LABORATORY MmOSm Hi Advanced Gun System ( AGS ) Dynamic Characterization: Modal Test and Analysis, High-Frequency Analysis by Morris...this report when it is no longer needed. Do not return it to the originator. ERRATA SHEET re: ARL-TR-2138 "Advanced Gun System ( AGS ) Dynamic

Solar air heating system: design and dynamic simulation

NASA Astrophysics Data System (ADS)

Bououd, M.; Hachchadi, O.; Janusevicius, K.; Martinaitis, V.; Mechaqrane, A.

2018-05-01

The building sector is one of the big energy consumers in Morocco, accounting for about 23% of the country’s total energy consumption. Regarding the population growth, the modern lifestyle requiring more comfort and the increase of the use rate of electronic devices, the energy consumption will continue to increase in the future. In this context, the introduction of renewable energy systems, along with energy efficiency, is becoming a key factor in reducing the energy bill of buildings. This study focuses on the design and dynamic simulation of an air heating system for the mean categories of the tertiary sector where the area exceeds 750 m3. Heating system has been designed via a dynamic simulation environment (TRNSYS) to estimate the produced temperature and airflow rate by one system consisting of three essential components: vacuum tube solar collector, storage tank and water-to-air finned heat exchanger. The performances estimation of this system allows us to evaluate its capacity to meet the heating requirements in Ifrane city based on the prescriptive approach according to the Moroccan Thermal Regulation. The simulation results show that in order to maintain a comfort temperature of 20°C in a building of 750m3, the places requires a thermal powers of approximately 21 kW, 29 kW and 32 kW, respectively, for hotels, hospitals, administrative and public-school. The heat generation is ensured by a solar collector areas of 5 m², 7 m² and 10 m², respectively, for hotels, hospitals, administrative and public-school spaces, a storage tank of 2 m3 and a finned heat exchanger with 24 tubes. The finned tube bundles have been modelled and integrated into the system design via a Matlab code. The heating temperature is adjusted via two controllers to ensure a constant air temperature of 20°C during the heating periods.

Advance Ratio Effects on the Dynamic-stall Vortex of a Rotating Blade in Steady Forward Flight

DTIC Science & Technology

2014-08-06

dependence on advance ratio is used to relate the stability of the dynamic-stall vortex to Coriolis effects . Advance ratio effects on the dynamic-stall vortex...relate the stability of the dynamic-stall vortex to Coriolis effects . Keywords: Leading-edge vortex, Dynamic stall vortex, Vortex flows, Rotating wing...Reynolds number are not decoupled. 3. Radial flow field In the rotating environment the coupled effect of centripetal and Coriolis accelerations is ex

The effect of the low Earth orbit environment on space solar cells: Results of the advanced photovoltaic experiment (S0014)

NASA Technical Reports Server (NTRS)

Brinker, David J.; Hickey, John R.

1992-01-01

The Advanced Photovoltaic Experiment (APEX), containing over 150 solar cells and sensors, was designed to generate laboratory reference standards as well as to explore the durability of a wide variety of space solar cells. Located on the leading edge of the Long Duration Exposure Facility (LDEF), APEX received the maximum possible dosage of atomic oxygen and ultraviolet radiation, as well as enormous numbers of impacts from micrometeoroids and debris. The effect of the low earth orbital (LEO) environment on the solar cells and materials of APEX will be discussed in this paper. The on-orbit performance of the solar cells, as well as a comparison of pre- and postflight laboratory performance measurements, will be presented.

Thermodynamic and dynamic responses of the hydrological cycle to solar dimming

NASA Astrophysics Data System (ADS)

Smyth, Jane E.; Russotto, Rick D.; Storelvmo, Trude

2017-05-01

The fundamental role of the hydrological cycle in the global climate system motivates a thorough evaluation of its responses to climate change and mitigation. The Geoengineering Model Intercomparison Project (GeoMIP) is a coordinated international effort to assess the climate impacts of solar geoengineering, a proposal to counteract global warming with a reduction in incoming solar radiation. We assess the mechanisms underlying the rainfall response to a simplified simulation of such solar dimming (G1) in the suite of GeoMIP models and identify robust features. While solar geoengineering nearly restores preindustrial temperatures, the global hydrology is altered. Tropical precipitation changes dominate the response across the model suite, and these are driven primarily by shifts of the Hadley circulation cells. We report a damping of the seasonal migration of the Intertropical Convergence Zone (ITCZ) in G1, associated with preferential cooling of the summer hemisphere, and annual mean ITCZ shifts in some models that are correlated with the warming of one hemisphere relative to the other. Dynamical changes better explain the varying tropical rainfall anomalies between models than changes in relative humidity or the Clausius-Clapeyron scaling of precipitation minus evaporation (P - E), given that the relative humidity and temperature responses are robust across the suite. Strong reductions in relative humidity over vegetated land regions are likely related to the CO2 physiological response in plants. The uncertainty in the spatial distribution of tropical P - E changes highlights the need for cautious consideration and continued study before any implementation of solar geoengineering.

Early solar system. Early accretion of water in the inner solar system from a carbonaceous chondrite-like source.

PubMed

Sarafian, Adam R; Nielsen, Sune G; Marschall, Horst R; McCubbin, Francis M; Monteleone, Brian D

2014-10-31

Determining the origin of water and the timing of its accretion within the inner solar system is important for understanding the dynamics of planet formation. The timing of water accretion to the inner solar system also has implications for how and when life emerged on Earth. We report in situ measurements of the hydrogen isotopic composition of the mineral apatite in eucrite meteorites, whose parent body is the main-belt asteroid 4 Vesta. These measurements sample one of the oldest hydrogen reservoirs in the solar system and show that Vesta contains the same hydrogen isotopic composition as that of carbonaceous chondrites. Taking into account the old ages of eucrite meteorites and their similarity to Earth's isotopic ratios of hydrogen, carbon, and nitrogen, we demonstrate that these volatiles could have been added early to Earth, rather than gained during a late accretion event. Copyright © 2014, American Association for the Advancement of Science.

Solar Innovator | Alta Devices

ScienceCinema

Mattos, Laila; Le, Minh

2017-12-09

Selected to participate in the Energy Department's SunShot Initiative, Alta Devices produces solar cells that convert sunlight into electricity at world record-breaking levels of efficiency. Through its innovative solar technology Alta is helping bring down the cost of solar. Learn more about the Energy Department's efforts to advance solar technology at energy.gov/solar .

Spectral mismatch and solar simulator quality factor in advanced LED solar simulators

NASA Astrophysics Data System (ADS)

Scherff, Maximilian L. D.; Nutter, Jason; Fuss-Kailuweit, Peter; Suthues, Jörn; Brammer, Torsten

2017-08-01

Solar cell simulators based on light emitting diodes (LED) have the potential to achieve a large potential market share in the next years. As advantages they can provide a short and long time stable spectrum, which fits very well to the global AM1.5g reference spectrum. This guarantees correct measurements during the flashes and throughout the light engines’ life span, respectively. Furthermore, a calibration with a solar cell type of different spectral response (SR) as well as the production of solar cells with varying SR in between two calibrations does not affect the correctness of the measurement result. A high quality 21 channel LED solar cell spectrum is compared to former study comprising a standard modified xenon spectrum light source. It is shown, that the spectrum of the 21-channel-LED light source performs best for all examined cases.

The Solar Dynamic radiator with a historical perspective

NASA Technical Reports Server (NTRS)

Mclallin, K. L.; Fleming, M. L.; Hoehn, F. W.; Howerton, R.

1988-01-01

A historical perspective on pumped loop space radiators provides a basis for the design of the Space Station Solar Dynamic (SD) power module radiator. SD power modules, capable of generating 25 kWe each, are planned for growth Station power requirements. The Brayton (cycle) SD module configuration incorporates a pumped loop radiator that must reject up to 99 kW. The thermal/hydraulic design conditions in combination with required radiator orientation and packaging envelope form a unique set of constraints as compared to previous pumped loop radiator systems. Nevertheless, past program successes have demonstrated a technology base which can be applied to the SD radiator development program to ensure a low risk, low cost system.

Specific cation interactions as the cause of slow dynamics and hysteresis in dye and perovskite solar cells: a small-perturbation study.

PubMed

Contreras, Lidia; Idígoras, Jesús; Todinova, Anna; Salado, Manuel; Kazim, Samrana; Ahmad, Shahzada; Anta, Juan A

2016-11-16

Hysteresis is one of the most remarkable features of perovskite solar cells; however, it is also present in other kinds of devices such as dye-sensitized solar cells. Hysteresis is due to underlying slow dynamic processes that interfere with the process of charge separation which depends critically on the selective contacts used. In this work we focus on the low-frequency (0.1-10 Hz) dynamics using impedance and intensity-modulated photocurrent spectroscopy and found that both perovskite solar cells (PSCs) and "viscous electrolyte containing" dye-sensitized solar cells (DSSCs) can be described on the same fundamental grounds. By comparing different electrolyte compositions in DSSCs and both methylammonium and formamidinium-based PSCs, we find a connection between the polar nature of the cations and the low-frequency component of these solar cells. There is evidence that in both cases ion transport and specific chemical interactions with the TiO 2 surface give rise to the slow dynamics and the hysteresis. This is mainly inferred from the slope of the capacitance vs. applied voltage which shows accumulation behavior for the formulations with higher dipole moments only.

Solar dynamic power for Earth orbital and lunar applications

NASA Technical Reports Server (NTRS)

Calogeras, James E.; Dustin, Miles O.; Secunde, Richard R.

1991-01-01

Development of solar dynamic (SD) technologies for space over the past 25 years by NASA Lewis Research Center brought SD power to the point where it was selected in the design phase of Space Station Freedom Program as the power source for evolutionary growth. More recent studies showed that large cost savings are possible in establishing manufacturing processes at a Lunar Base if SD is considered as a power source. Technology efforts over the past 5 years have made possible lighter, more durable, SD components for these applications. A review of these efforts and respective benefits is presented.

Charge Generation Dynamics in Efficient All-Polymer Solar Cells: Influence of Polymer Packing and Morphology.

PubMed

Gautam, Bhoj R; Lee, Changyeon; Younts, Robert; Lee, Wonho; Danilov, Evgeny; Kim, Bumjoon J; Gundogdu, Kenan

2015-12-23

All-polymer solar cells exhibit rapid progress in power conversion efficiency (PCE) from 2 to 7.7% over the past few years. While this improvement is primarily attributed to efficient charge transport and balanced mobility between the carriers, not much is known about the charge generation dynamics in these systems. Here we measured exciton relaxation and charge separation dynamics using ultrafast spectroscopy in polymer/polymer blends with different molecular packing and morphology. These measurements indicate that preferential face-on configuration with intermixed nanomorphology increases the charge generation efficiency. In fact, there is a direct quantitative correlation between the free charge population in the ultrafast time scales and the external quantum efficiency, suggesting not only the transport but also charge generation is key for the design of high performance all polymer solar cells.

Response of the coupled M-I-T system to the March 17, 2015 solar wind dynamic pressure enhancement event

NASA Astrophysics Data System (ADS)

Ozturk, D. S.; Zou, S.; Slavin, J. A.; Ridley, A. J.

2017-12-01

When the solar wind dynamic pressure is enhanced, it could perturb the global magnetosphere-ionosphere-thermosphere (M-I-T) system. The most notable indicators of such disruptions are changes in Field-Aligned Currents (FACs), ionospheric convection patterns and magnetic perturbations observed by ground magnetometers. The link between dynamic pressure enhancements and FACs has been well established, but studies on how these FACs affect the ionosphere-thermosphere system are very limited. In order to understand the large-scale dynamic processes in the M-I-T system due to the solar wind dynamic pressure enhancement, we study the 17 March 2015 event in detail. This is one of the most geoeffective events of the solar cycle 24 with Dst minimum of -222 nT. The Wind spacecraft recorded a two-step increment in the solar wind dynamic pressure, from 2 nPa to 12 nPa within 3 minutes, while the IMF Bz stayed northward. We used the University of Michigan Block Adaptive Tree Solarwind Roe Upwind Scheme (BATS'R'US), global MHD code to study the generation and propagation of perturbations associated with the compression of the magnetosphere. To effectively represent the coupled magnetosphere-ionosphere system, we included the Global Magnetosphere (GM), Inner Magnetosphere (IM) and Ionospheric electrodynamic (IE) modules. 600 uniformly distributed virtual magnetometers are included in the simulation to identify the magnetic perturbations associated with the FAC pairs as well as their temporal and spatial variations. In addition, we used the IE module output to drive the University of Michigan Global Ionosphere Thermosphere Model (GITM) to study how the I-T system responds to dynamic pressure enhancement. We show that as a result of the solar wind dynamic pressure enhancement, two pair of perturbation FACs develop in addition to the NBZ current system. These FACs significantly alter the ionospheric convection profile and create elongated vortices that propagate from dayside to

PROGRAM ASTEC (ADVANCED SOLAR TURBO ELECTRIC CONCEPT). PART IV. SOLAR COLLECTOR DEVELOPMENT SUPPORT TASKS. VOL. VI. DEVELOPMENT OF ANALYTICAL TECHNIQUES TO PREDICT THE STRUCTURAL BEHAVIOR OF PETAL-TYPE SOLAR COLLECTORS.

DTIC Science & Technology

The design of large petal-type paraboloidal solar collectors for the ASTEC Program requires a capability for determining the distortion and stress...analysis of a parabolic curved beam is given along with a numerical solution and digital program. The dynamic response of the ASTEC flight-test vehicle is discussed on the basis of modal analysis.

The FOXSI solar sounding rocket campaigns

NASA Astrophysics Data System (ADS)

Glesener, Lindsay; Krucker, Säm.; Christe, Steven; Ishikawa, Shin-nosuke; Buitrago-Casas, Juan Camilo; Ramsey, Brian; Gubarev, Mikhail; Takahashi, Tadayuki; Watanabe, Shin; Takeda, Shin'ichiro; Courtade, Sasha; Turin, Paul; McBride, Stephen; Shourt, Van; Hoberman, Jane; Foster, Natalie; Vievering, Juliana

2016-07-01

The Focusing Optics X-ray Solar Imager (FOXSI) is, in its initial form, a sounding rocket experiment designed to apply the technique of focusing hard X-ray (HXR) optics to the study of fundamental questions about the high-energy Sun. Solar HXRs arise via bremsstrahlung from energetic electrons and hot plasma produced in solar flares and thus are one of the most direct diagnostics of are-accelerated electrons and the impulsive heating of the solar corona. Previous missions have always been limited in sensitivity and dynamic range by the use of indirect (Fourier) imaging due to the lack of availability of direct focusing optics, but technological advances now make direct focusing accessible in the HXR regime (as evidenced by the NuSTAR spacecraft and several suborbital missions). The FOXSI rocket experiment develops and optimizes HXR focusing telescopes for the unique scientific requirements of the Sun. To date, FOXSI has completed two successful flights on 2012 November 02 and 2014 December 11 and is funded for a third flight. This paper gives a brief overview of the experiment, which is sensitive to solar HXRs in the 4-20 keV range, describes its first two flights, and gives a preview of plans for FOXSI-3.

The FOXSI Solar Sounding Rocket Campaigns

NASA Technical Reports Server (NTRS)

Glesener, Lindsay; Krucker, Sam; Christe, Steven; Ishikawa, Shin-Nosuke; Buitrago-Casas, Juan Camilo; Ramsey, Brian; Gubarev, Mikhail; Takahashi, Tadayuki; Watanabe, Shin; Takeda, Shin'ichiro;

The Effects of Propellant Slosh Dynamics on the Solar Dynamics Observatory

NASA Technical Reports Server (NTRS)

Mason, Paul; Starin, Scott R.

2011-01-01

The Solar Dynamics Observatory (SDO) mission, which is part of the Living With a Star program, was successfully launched and deployed from its Atlas V launch vehicle on February 11, 2010. SDO is an Explorer-class mission now operating in a geosynchronous orbit (GEO). The basic mission is to observe the Sun for a very high percentage of the 5-year mission (10-year goal) with long stretches of uninterrupted observations and with constant, high-data-rate transmission to a dedicated ground station located in White Sands, New Mexico. Almost half of SDO's launch mass was propellant, contained in two large tanks. To ensure performance with this amount of propellant, a slosh analysis was performed prior to launch. This paper provides an overview of the SDO slosh analysis, the on-orbit experience, and the lessons learned.

The Effects of Propellant Slosh Dynamics on the Solar Dynamics Observatory

NASA Technical Reports Server (NTRS)

Mason, Paul; Starin, Scott R.

2011-01-01

The Solar Dynamics Observatory (SOO) mission, which is part of the Living With a Star program, was successfully launched and deployed from its Atlas V launch vehicle on February 11, 2010. SOO is an Explorer-class mission now operating in a geosynchronous orbit (GEO). The basic mission is to observe the Sun for a very high percentage of the 5-year mission (10-year goal) with long stretches of uninterrupted observations and with constant, high-data-rate transmission to a dedicated ground station located in White Sands, New Mexico. Almost half of SDO's launch mass was propellant, contained in two large tanks. To ensure performance with this amount of propellant, a slosh analysis was performed prior to launch. This paper provides an overview of the SDO slosh analysis, the on-orbit experience, and the lessons learned.

Solar dynamic heat receiver technology

NASA Technical Reports Server (NTRS)

Sedgwick, Leigh M.

1991-01-01

A full-size, solar dynamic heat receiver was designed to meet the requirements specified for electrical power modules on the U.S. Space Station, Freedom. The heat receiver supplies thermal energy to power a heat engine in a closed Brayton cycle using a mixture of helium-xenon gas as the working fluid. The electrical power output of the engine, 25 kW, requires a 100 kW thermal input throughout a 90 minute orbit, including when the spacecraft is eclipsed for up to 36 minutes from the sun. The heat receiver employs an integral thermal energy storage system utilizing the latent heat available through the phase change of a high-temperature salt mixture. A near eutectic mixture of lithium fluoride and calcium difluoride is used as the phase change material. The salt is contained within a felt metal matrix which enhances heat transfer and controls the salt void distribution during solidification. Fabrication of the receiver is complete and it was delivered to NASA for verification testing in a simulated low-Earth-orbit environment. This document reviews the receiver design and describes its fabrication history. The major elements required to operate the receiver during testing are also described.

Solar concentrator technology development for space based applications, volume 1

NASA Technical Reports Server (NTRS)

Pintz, A.; Castle, C. H.; Reimer, R. R.

1992-01-01

Thermoelectric conversion using a radio-isotope heat source has been used where outer planetary space craft are too far away for absorbing significant solar energy. Solar dynamic power (SDP) conversion is one technology that offers advantages for applications within the inner planet region. Since SDP conversion efficiency can be 2 to 3 times higher than photovoltaic, the collecting surfaces are much reduced in area and therefore lighter. This becomes an advantage in allocating more weight to launched payloads. A second advantage results for low earth orbit applications. The reduced area results in lower drag forces on the spacecraft and requires less reboost propellant to maintain orbit. A third advantage occurs because of the sun-to-shade cycling while in earth orbit. Photovoltaic systems require batteries to store energy for use when in the shade, and battery life for periods of 10 to 15 years is not presently achievable. For these reasons the Solar Dynamics and Thermal Systems Branch at NASA LeRC has funded work in developing SDP systems. The generic SDP system uses a large parabolic solar concentrator to focus solar energy onto a power conversion device. The concentrators are large areas and must therefore be efficient and have low specific weights. Yet these surfaces must be precise and capable of being stowed in a launch vehicle and then deployed and sometimes unfurled in space. There are significant technical challenges in engineering such structures, and considerable investigation has been made to date. This is the first of two volumes reporting on the research done by the Advanced Manufacturing Center at Cleveland State University to assist NASA LeRC in evaluating this technology. The objective of the grant was to restore the solar concentrator development technology of the 1960s while improving it with advances that have occurred since then. This report summarizes the work done from January 1989 through December 1991.

Solar concentrator technology development for space based applications, volume 2

NASA Technical Reports Server (NTRS)

Pintz, A.; Castle, C. H.; Reimer, R. R.

1992-01-01

Thermoelectric conversion using a radio-isotope heat source has been used where outer planetary space craft are too far away for absorbing significant solar energy. Solar dynamic power (SDP) conversion is one technology that offers advantages for applications within the inner planet region. Since SDP conversion efficiency can be 2 to 3 times higher than photovoltaic, the collecting surfaces are much reduced in area and therefore lighter. This becomes an advantage in allocating more weight to launched payloads. A second advantage results for low earth orbit applications. The reduced area results in lower drag forces on the spacecraft and requires less reboost propellant to maintain orbit. A third advantage occurs because of the sun-to-shade cycling while in earth orbit. Photovoltaic systems require batteries to store energy for use when in the shade, and battery life for periods of 10 to 15 years is not presently achievable. For these reasons the Solar Dynamics and Thermal Systems Branch at NASA LeRC has funded work in developing SDP systems. The generic SDP system uses a large parabolic solar concentrator to focus solar energy onto a power conversion device. The concentrators are large areas and must therefore be efficient and have low specific weights. Yet these surfaces must be precise and capable of being stowed in a launch vehicle and then deployed and sometimes unfurled in space. There are significant technical challenges in engineering such structures, and considerable investigation has been made to date. This is the second of two volumes reporting on the research done by the Advanced Manufacturing Center at Cleveland State University to assist NASA LeRC in evaluating this technology. This volume includes the appendices of selected data sets, drawings, and procedures. The objective of the grant was to restore the solar concentrator development technology of the 1960s while improving it with advances that have occurred since then. This report summarizes the

On the Performance of Multi-Instrument Solar Flare Observations During Solar Cycle 24

NASA Astrophysics Data System (ADS)

Milligan, Ryan O.; Ireland, Jack

2018-02-01

The current fleet of space-based solar observatories offers us a wealth of opportunities to study solar flares over a range of wavelengths. Significant advances in our understanding of flare physics often come from coordinated observations between multiple instruments. Consequently, considerable efforts have been, and continue to be, made to coordinate observations among instruments ( e.g. through the Max Millennium Program of Solar Flare Research). However, there has been no study to date that quantifies how many flares have been observed by combinations of various instruments. Here we describe a technique that retrospectively searches archival databases for flares jointly observed by the Ramaty High Energy Solar Spectroscopic Imager (RHESSI), Solar Dynamics Observatory (SDO)/ EUV Variability Experiment (EVE - Multiple EUV Grating Spectrograph (MEGS)-A and -B, Hinode/( EUV Imaging Spectrometer, Solar Optical Telescope, and X-Ray Telescope), and Interface Region Imaging Spectrograph (IRIS). Out of the 6953 flares of GOES magnitude C1 or greater that we consider over the 6.5 years after the launch of SDO, 40 have been observed by 6 or more instruments simultaneously. Using each instrument's individual rate of success in observing flares, we show that the numbers of flares co-observed by 3 or more instruments are higher than the number expected under the assumption that the instruments operated independently of one another. In particular, the number of flares observed by larger numbers of instruments is much higher than expected. Our study illustrates that these missions often acted in cooperation, or at least had aligned goals. We also provide details on an interactive widget ( Solar Flare Finder), now available in SSWIDL, which allows a user to search for flaring events that have been observed by a chosen set of instruments. This provides access to a broader range of events in order to answer specific science questions. The difficulty in scheduling coordinated

Simultaneous control of multiple instruments at the Advanced Technology Solar Telescope

NASA Astrophysics Data System (ADS)

Johansson, Erik M.; Goodrich, Bret

2012-09-01

The Advanced Technology Solar Telescope (ATST) is a 4-meter solar observatory under construction at Haleakala, Hawaii. The simultaneous use of multiple instruments is one of the unique capabilities that makes the ATST a premier ground based solar observatory. Control of the instrument suite is accomplished by the Instrument Control System (ICS), a layer of software between the Observatory Control System (OCS) and the instruments. The ICS presents a single narrow interface to the OCS and provides a standard interface for the instruments to be controlled. It is built upon the ATST Common Services Framework (CSF), an infrastructure for the implementation of a distributed control system. The ICS responds to OCS commands and events, coordinating and distributing them to the various instruments while monitoring their progress and reporting the status back to the OCS. The ICS requires no specific knowledge about the instruments. All information about the instruments used in an experiment is passed by the OCS to the ICS, which extracts and forwards the parameters to the appropriate instrument controllers. The instruments participating in an experiment define the active instrument set. A subset of those instruments must complete their observing activities in order for the experiment to be considered complete and are referred to as the must-complete instrument set. In addition, instruments may participate in eavesdrop mode, outside of the control of the ICS. All instrument controllers use the same standard narrow interface, which allows new instruments to be added without having to modify the interface or any existing instrument controllers.

Analysis of solar receiver flux distributions for US/Russian solar dynamic system demonstration on the MIR Space Station

NASA Technical Reports Server (NTRS)

Kerslake, Thomas W.; Fincannon, James

1995-01-01

The United States and Russia have agreed to jointly develop a solar dynamic (SD) system for flight demonstration on the Russian MIR space station starting in late 1997. Two important components of this SD system are the solar concentrator and heat receiver provided by Russia and the U.S., respectively. This paper describes optical analysis of the concentrator and solar flux predictions on target receiver surfaces. The optical analysis is performed using the code CIRCE2. These analyses account for finite sun size with limb darkening, concentrator surface slope and position errors, concentrator petal thermal deformation, gaps between petals, and the shading effect of the receiver support struts. The receiver spatial flux distributions are then combined with concentrator shadowing predictions. Geometric shadowing patterns are traced from the concentrator to the target receiver surfaces. These patterns vary with time depending on the chosen MIR flight attitude and orbital mechanics of the MIR spacecraft. The resulting predictions provide spatial and temporal receiver flux distributions for any specified mission profile. The impact these flux distributions have on receiver design and control of the Brayton engine are discussed.

Photocatalytic Removal of Microcystin-LR by Advanced WO3-Based Nanoparticles under Simulated Solar Light

PubMed Central

Zhao, Chao; Li, Dawei; Feng, Chuanping; Zhang, Zhenya; Sugiura, Norio; Yang, Yingnan

2015-01-01

A series of advanced WO3-based photocatalysts including CuO/WO3, Pd/WO3, and Pt/WO3 were synthesized for the photocatalytic removal of microcystin-LR (MC-LR) under simulated solar light. In the present study, Pt/WO3 exhibited the best performance for the photocatalytic degradation of MC-LR. The MC-LR degradation can be described by pseudo-first-order kinetic model. Chloride ion (Cl−) with proper concentration could enhance the MC-LR degradation. The presence of metal cations (Cu2+ and Fe3+) improved the photocatalytic degradation of MC-LR. This study suggests that Pt/WO3 photocatalytic oxidation under solar light is a promising option for the purification of water containing MC-LR. PMID:25884038

Preliminary design of an advanced Stirling system for terrestrial solar energy conversion

NASA Astrophysics Data System (ADS)

White, M. A.; Noble, J. E.; Emigh, S. G.; Ross, B. A.; Lehmann, G. A.

A preliminary design was generated for an advanced Stirling conversion system (ASCS) that will be capable of delivering about 25 kW of electric power to an electric utility grid. Stirling engines are being evaluated for terrestrial solar applications. A two-year task to complete detailed design, fabrication, assembly and testing of an ASCS prototype began in April, 1990. The ASCS is designed to deliver maximum power per year over a range of solar inputs with a design life of 30 years (60,000 h). The ACSC has a long-term cost goal of about $450 per kilowatt, exclusive of the 11-m parabolic dish concentrator. The proposed system includes a Stirling engine with high-pressure hydraulic output, coupled with a bent axis variable displacement hydraulic motor and a rotary induction generator. The major thrusts of the preliminary design are described, including material selection for the hot-end components, heat transport system (reflux pool boiler) design, system thermal response, improved manufacturability, FMECA/FTA analysis, updated manufacturing cost estimate, and predicted system performance.

Preliminary design of an advanced Stirling system for terrestrial solar energy conversion

NASA Technical Reports Server (NTRS)

White, M. A.; Noble, J. E.; Emigh, S. G.; Ross, B. A.; Lehmann, G. A.

1990-01-01

A preliminary design was generated for an advanced Stirling conversion system (ASCS) that will be capable of delivering about 25 kW of electric power to an electric utility grid. Stirling engines are being evaluated for terrestrial solar applications. A two-year task to complete detailed design, fabrication, assembly and testing of an ASCS prototype began in April, 1990. The ASCS is designed to deliver maximum power per year over a range of solar inputs with a design life of 30 years (60,000 h). The ACSC has a long-term cost goal of about $450 per kilowatt, exclusive of the 11-m parabolic dish concentrator. The proposed system includes a Stirling engine with high-pressure hydraulic output, coupled with a bent axis variable displacement hydraulic motor and a rotary induction generator. The major thrusts of the preliminary design are described, including material selection for the hot-end components, heat transport system (reflux pool boiler) design, system thermal response, improved manufacturability, FMECA/FTA analysis, updated manufacturing cost estimate, and predicted system performance.

Concentrating solar power (CSP) power cycle improvements through application of advanced materials

NASA Astrophysics Data System (ADS)

Siefert, John A.; Libby, Cara; Shingledecker, John

2016-05-01

Concentrating solar power (CSP) systems with thermal energy storage (TES) capability offer unique advantages to other renewable energy technologies in that solar radiation can be captured and stored for utilization when the sun is not shining. This makes the technology attractive as a dispatchable resource, and as such the Electric Power Research Institute (EPRI) has been engaged in research and development activities to understand and track the technology, identify key technical challenges, and enable improvements to meet future cost and performance targets to enable greater adoption of this carbon-free energy resource. EPRI is also involved with technically leading a consortium of manufacturers, government labs, and research organizations to enable the next generation of fossil fired power plants with advanced ultrasupercritical (A-USC) steam temperatures up to 760°C (1400°F). Materials are a key enabling technology for both of these seemingly opposed systems. This paper discusses how major strides in structural materials for A-USC fossil fired power plants may be translated into improved CSP systems which meet target requirements.

Dynamic modeling and optimal joint torque coordination of advanced robotic systems

NASA Astrophysics Data System (ADS)

Kang, Hee-Jun

The development is documented of an efficient dynamic modeling algorithm and the subsequent optimal joint input load coordination of advanced robotic systems for industrial application. A closed-form dynamic modeling algorithm for the general closed-chain robotic linkage systems is presented. The algorithm is based on the transfer of system dependence from a set of open chain Lagrangian coordinates to any desired system generalized coordinate set of the closed-chain. Three different techniques for evaluation of the kinematic closed chain constraints allow the representation of the dynamic modeling parameters in terms of system generalized coordinates and have no restriction with regard to kinematic redundancy. The total computational requirement of the closed-chain system model is largely dependent on the computation required for the dynamic model of an open kinematic chain. In order to improve computational efficiency, modification of an existing open-chain KIC based dynamic formulation is made by the introduction of the generalized augmented body concept. This algorithm allows a 44 pct. computational saving over the current optimized one (O(N4), 5995 when N = 6). As means of resolving redundancies in advanced robotic systems, local joint torque optimization is applied for effectively using actuator power while avoiding joint torque limits. The stability problem in local joint torque optimization schemes is eliminated by using fictitious dissipating forces which act in the necessary null space. The performance index representing the global torque norm is shown to be satisfactory. In addition, the resulting joint motion trajectory becomes conservative, after a transient stage, for repetitive cyclic end-effector trajectories. The effectiveness of the null space damping method is shown. The modular robot, which is built of well defined structural modules from a finite-size inventory and is controlled by one general computer system, is another class of evolving

Stochastic Modelling, Analysis, and Simulations of the Solar Cycle Dynamic Process

NASA Astrophysics Data System (ADS)

Turner, Douglas C.; Ladde, Gangaram S.

2018-03-01

Analytical solutions, discretization schemes and simulation results are presented for the time delay deterministic differential equation model of the solar dynamo presented by Wilmot-Smith et al. In addition, this model is extended under stochastic Gaussian white noise parametric fluctuations. The introduction of stochastic fluctuations incorporates variables affecting the dynamo process in the solar interior, estimation error of parameters, and uncertainty of the α-effect mechanism. Simulation results are presented and analyzed to exhibit the effects of stochastic parametric volatility-dependent perturbations. The results generalize and extend the work of Hazra et al. In fact, some of these results exhibit the oscillatory dynamic behavior generated by the stochastic parametric additative perturbations in the absence of time delay. In addition, the simulation results of the modified stochastic models influence the change in behavior of the very recently developed stochastic model of Hazra et al.

Dynamic modelling and simulation of linear Fresnel solar field model based on molten salt heat transfer fluid

NASA Astrophysics Data System (ADS)

Hakkarainen, Elina; Tähtinen, Matti

2016-05-01

Demonstrations of direct steam generation (DSG) in linear Fresnel collectors (LFC) have given promising results related to higher steam parameters compared to the current state-of-the-art parabolic trough collector (PTC) technology using oil as heat transfer fluid (HTF). However, DSG technology lacks feasible solution for long-term thermal energy storage (TES) system. This option is important for CSP technology in order to offer dispatchable power. Recently, molten salts have been proposed to be used as HTF and directly as storage medium in both line-focusing solar fields, offering storage capacity of several hours. This direct molten salt (DMS) storage concept has already gained operational experience in solar tower power plant, and it is under demonstration phase both in the case of LFC and PTC systems. Dynamic simulation programs offer a valuable effort for design and optimization of solar power plants. In this work, APROS dynamic simulation program is used to model a DMS linear Fresnel solar field with two-tank TES system, and example simulation results are presented in order to verify the functionality of the model and capability of APROS for CSP modelling and simulation.

Recent Advances in Understanding Particle Acceleration Processes in Solar Flares

NASA Astrophysics Data System (ADS)

Zharkova, V. V.; Arzner, K.; Benz, A. O.; Browning, P.; Dauphin, C.; Emslie, A. G.; Fletcher, L.; Kontar, E. P.; Mann, G.; Onofri, M.; Petrosian, V.; Turkmani, R.; Vilmer, N.; Vlahos, L.

2011-09-01

We review basic theoretical concepts in particle acceleration, with particular emphasis on processes likely to occur in regions of magnetic reconnection. Several new developments are discussed, including detailed studies of reconnection in three-dimensional magnetic field configurations (e.g., current sheets, collapsing traps, separatrix regions) and stochastic acceleration in a turbulent environment. Fluid, test-particle, and particle-in-cell approaches are used and results compared. While these studies show considerable promise in accounting for the various observational manifestations of solar flares, they are limited by a number of factors, mostly relating to available computational power. Not the least of these issues is the need to explicitly incorporate the electrodynamic feedback of the accelerated particles themselves on the environment in which they are accelerated. A brief prognosis for future advancement is offered.

Badhwar-O'Neil 2007 Galactic Cosmic Ray (GCR) Model Using Advanced Composition Explorer (ACE) Measurements for Solar Cycle 23

NASA Technical Reports Server (NTRS)

ONeill, P. M.

2007-01-01

Advanced Composition Explorer (ACE) satellite measurements of the galactic cosmic ray flux and correlation with the Climax Neutron Monitor count over Solar Cycle 23 are used to update the Badhwar O'Neill Galactic Cosmic Ray (GCR) model.

Nonlinear Dynamic Models in Advanced Life Support

NASA Technical Reports Server (NTRS)

Jones, Harry

2002-01-01

To facilitate analysis, ALS systems are often assumed to be linear and time invariant, but they usually have important nonlinear and dynamic aspects. Nonlinear dynamic behavior can be caused by time varying inputs, changes in system parameters, nonlinear system functions, closed loop feedback delays, and limits on buffer storage or processing rates. Dynamic models are usually cataloged according to the number of state variables. The simplest dynamic models are linear, using only integration, multiplication, addition, and subtraction of the state variables. A general linear model with only two state variables can produce all the possible dynamic behavior of linear systems with many state variables, including stability, oscillation, or exponential growth and decay. Linear systems can be described using mathematical analysis. Nonlinear dynamics can be fully explored only by computer simulations of models. Unexpected behavior is produced by simple models having only two or three state variables with simple mathematical relations between them. Closed loop feedback delays are a major source of system instability. Exceeding limits on buffer storage or processing rates forces systems to change operating mode. Different equilibrium points may be reached from different initial conditions. Instead of one stable equilibrium point, the system may have several equilibrium points, oscillate at different frequencies, or even behave chaotically, depending on the system inputs and initial conditions. The frequency spectrum of an output oscillation may contain harmonics and the sums and differences of input frequencies, but it may also contain a stable limit cycle oscillation not related to input frequencies. We must investigate the nonlinear dynamic aspects of advanced life support systems to understand and counter undesirable behavior.

Solar dynamic heat receiver thermal characteristics in low earth orbit

NASA Technical Reports Server (NTRS)

Wu, Y. C.; Roschke, E. J.; Birur, G. C.

1988-01-01

A simplified system model is under development for evaluating the thermal characteristics and thermal performance of a solar dynamic spacecraft energy system's heat receiver. Results based on baseline orbit, power system configuration, and operational conditions, are generated for three basic receiver concepts and three concentrator surface slope errors. Receiver thermal characteristics and thermal behavior in LEO conditions are presented. The configuration in which heat is directly transferred to the working fluid is noted to generate the best system and thermal characteristics. as well as the lowest performance degradation with increasing slope error.

The dynamics and control of solar-sail spacecraft in displaced lunar orbits

NASA Astrophysics Data System (ADS)

Wawrzyniak, Geoffrey George

Trajectory generation for any spacecraft mission application typically involves either well-developed analytical approximations or a linearization with respect to a known solution. Such approximations are based on the well-understood dynamics of behavior in the system. However, when two or more large bodies (e.g., the Earth and the Moon or the Sun, the Earth and the Moon) are present, trajectories in the multi-body gravitational field can evolve chaotically. The problem is further complicated when an additional force from a solar sail is included. Solar sail trajectories are often developed in a Sun-centered reference frame in which the sunlight direction is fixed. New challenges arise when modeling a solar-sail trajectory in a reference frame attached to the Earth and the Moon (a frame that rotates in inertial space). Advantages accrue from geometry and symmetry properties that are available in this Earth--Moon reference frame, but the Sun location and the sunlight direction change with time. Current trajectory design tools can reveal many solutions within these regimes. Recent work using numerical boundary value problem (BVP) solvers has demonstrated great promise for uncovering additional and, sometimes, "better" solutions to problems in spacecraft trajectory design involving solar sails. One such approach to solving BVPs is the finite-difference method. Derivatives that appear in the differential equations are replaced with their respective finite differences and evaluated at node points along the trajectory. The solution process is iterative. A candidate solution, such as an offset circle or a point, is discretized into nodes, and the equations that represent the relationships at the nodes are solved simultaneously. Finite-difference methods (FDMs) exploit coarse initial approximations and, with the system constraints (such as the continuous visibility of the spacecraft from a point on the lunar surface), to develop orbital solutions in regions where the

A New Set of Solar Fireworks

NASA Image and Video Library

2017-12-08

NASA's Solar Dynamics Observatory (SDO) captured this image of an M9-class flare on Oct 20, 2012 at 2:14 p.m. EDT. This image shows light at a wavelength of 131 Angstroms, which corresponds to material at 10 million Kelvin, and is a good wavelength for observing flares. This wavelength is typically colorized as teal, as shown here. To read more go to: www.nasa.gov/mission_pages/sunearth/news/News102012-m9fla... Credit: NASA/GSFC/SDO NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Overview of NASA's Space Solar Power Technology Advanced Research and Development Program

NASA Technical Reports Server (NTRS)

Howell, Joe; Mankins, John C.; Davis, N. Jan (Technical Monitor)

2001-01-01

Large solar power satellite (SPS) systems that might provide base load power into terrestrial markets were examined extensively in the 1970s by the US Department of Energy (DOE) and the National Aeronautics and Space Administration (NASA). Following a hiatus of about 15 years, the subject of space solar power (SSP) was reexamined by NASA from 1995-1997 in the 'fresh look' study, and during 1998 in an SSP 'concept definition study', and during 1999-2000 in the SSP Exploratory Research and Technology (SERT) program. As a result of these efforts, during 2001, NASA has initiated the SSP Technology Advanced Research and Development (STAR-Dev) program based on informed decisions. The goal of the STAR-Dev program is to conduct preliminary strategic technology research and development to enable large, multi-megawatt to gigawatt-class space solar power (SSP) systems and wireless power transmission (WPT) for government missions and commercial markets (in-space and terrestrial). Specific objectives include: (1) Release a NASA Research Announcement (NRA) for SSP Projects; (2) Conduct systems studies; (3) Develop Component Technologies; (4) Develop Ground and Flight demonstration systems; and (5) Assess and/or Initiate Partnerships. Accomplishing these objectives will allow informed future decisions regarding further SSP and related research and development investments by both NASA management and prospective external partners. In particular, accomplishing these objectives will also guide further definition of SSP and related technology roadmaps including performance objectives, resources and schedules; including 'multi-purpose' applications (commercial, science, and other government).

The solar dynamic radiator with a historical perspective

NASA Technical Reports Server (NTRS)

Mclallin, K. L.; Fleming, M. L.; Hoehn, F. W.; Howerton, R. L.

1988-01-01

A historical perspective on pumped-fluid loop space radiators provides a basis for the design of the Space Station Solar Dynamic (SD) power module radiator. SD power modules, capable of generating 25 kW (electrical) each, are planned for growth in Station power requirements. The Brayton cycle SD module configuration incorporates a pumped-fluid loop radiator that must reject up to 99 kW (thermal). The thermal/hydraulic design conditions in combination with required radiator orientation and packaging envelope form a unique set of constraints as compared to previous pumped-fluid loop radiator systems. Nevertheless, past program successes have demonstrated a technology base that can be applied to the SD radiator development program to ensure a low risk, low cost system.

NREL + SolarCity: Maximizing Solar Power on Electrical Grids

ScienceCinema

Hannegan, Bryan; Hanley, Ryan; Symko-Davies, Marth

2018-05-23

Learn how NREL is partnering with SolarCity to study how to better integrate rooftop solar onto the grid. The work includes collaboration with the Hawaiian Electric Companies (HECO) to analyze high-penetration solar scenarios using advanced modeling and inverter testing at the Energy Systems Integration Facility (ESIF) on NREL’s campus. Results to date have been so promising that HECO has more than doubled the amount of rooftop solar it allows on its grid, showing utilities across the country that distributed solar is not a liability for reliability—and can even be an asset.

Galaxy and the solar system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smoluchowski, R.; Bahcall, J.M.; Matthews, M.S.

1986-01-01

The solar-Galactic neighborhood, massive interstellar clouds and other Galactic features, the Oort cloud, perturbations of the solar system, and the existence and stability of a solar companion star are examined in chapters based on contributions to a conference held in Tucson, AZ during January 1985. The individual topics addressed include: the Galactic environment of the solar system; stars within 25 pc of the sun; the path of the sun in 100 million years; the local velocity field in the last billion years; interstellar clouds near the sun; and evidence for a local recent supernova. Also considered are: dynamic influence ofmore » Galactic tides and molecular clouds on the Oort cloud; cometary evidence for a solar companion; dynamical interactions between the Oort cloud and the Galaxy; geological periodicities and the Galaxy; giant comets and the Galaxy; dynamical evidence for Planet X; evolution of the solar system in the presence of a solar companion star; mass extinctions, crater ages, and comet showers; evidence for Nemesis, a solar companion star.« less

Solar Technology Acceleration Center (SolarTAC): Solar Resource & Meteorological Assessment Project (SOLRAMP)

DOE Data Explorer

Andreas, Afshin; Wilcox, Steve

2016-03-14

Located in Colorado, near Denver International Airport, SolarTAC is a private, member-based, 74-acre outdoor facility where the solar industry tests, validates, and demonstrates advanced solar technologies. SolarTAC was launched in 2008 by a public-private consortium, including Midwest Research Institute (MRI). As a supporting member of SolarTAC, the U.S. Department of Energy National Renewable Energy Laboratory (NMREL) has established a high quality solar and meteorological measurement station at this location. This Solar Resource and Meteorological Assessment Project (SOLRMAP) provides high quality measurements to support deployment of power projects in the United States. The no-funds-exchanged collaboration brings NREL solar resource assessment expertise together with industry needs for measurements. The end result is high quality data sets to support the financing, design, and monitoring of large scale solar powered projects for industry in addition to research-quality data for NREL model development. NREL provides consultation for instrumentation and station deployment, along with instrument calibrations, data acquisition, quality assessment, data distribution, and summary reports. Industry participants provide equipment, infrastructure, and station maintenance.

The effects of regional insolation differences upon advanced solar thermal electric power plant performance and energy costs

NASA Technical Reports Server (NTRS)

Latta, A. F.; Bowyer, J. M.; Fujita, T.; Richter, P. H.

1979-01-01

The performance and cost of the 10 MWe advanced solar thermal electric power plants sited in various regions of the continental United States were determined. The regional insolation data base is discussed. A range for the forecast cost of conventional electricity by region and nationally over the next several cades are presented.

Numerical model of solar dynamic radiator for parametric analysis

NASA Technical Reports Server (NTRS)

Rhatigan, Jennifer L.

1989-01-01

Growth power requirements for Space Station Freedom will be met through addition of 25 kW solar dynamic (SD) power modules. Extensive thermal and power cycle modeling capabilities have been developed which are powerful tools in Station design and analysis, but which prove cumbersome and costly for simple component preliminary design studies. In order to aid in refining the SD radiator to the mature design stage, a simple and flexible numerical model was developed. The model simulates heat transfer and fluid flow performance of the radiator and calculates area mass and impact survivability for many combinations of flow tube and panel configurations, fluid and material properties, and environmental and cycle variations.

Magnetic Reconfiguration in Explosive Solar Activity

NASA Technical Reports Server (NTRS)

Antiochos, Spiro K.

2008-01-01

A fundamental property of the Sun's corona i s that it is violently dynamic. The most spectacular and most energetic manifestations of this activity are the giant disruptions that give rise to coronal mass ejections (CME) and eruptive flares. These major events are of critical importance, because they drive the most destructive forms of space weather at Earth and in the solar system, and they provide a unique opportunity to study, in revealing detail, the interaction of magnetic field and matter, in particular, magnetohydrodynamic instability and nonequilibrium -- processes that are at the heart of laboratory and astrophysical plasma physics. Recent observations by a number of NASA space missions have given us new insights into the physical mechanisms that underlie coronal explosions. Furthermore, massively-parallel computation have now allowed us to calculate fully three-dimensional models for solar activity. In this talk I will present some of the latest observations of the Sun, including those from the just-launched Hinode and STEREO mission, and discuss recent advances in the theory and modeling of explosive solar activity.

Advances in Stereoconvergent Catalysis from 2005–2015: Transition-Metal-Mediated Stereoablative Reactions, Dynamic Kinetic Resolutions, and Dynamic Kinetic Asymmetric Transformations

PubMed Central

Bhat, Vikram; Welin, Eric R.; Guo, Xuelei; Stoltz, Brian M.

2017-01-01

An important subset of asymmetric synthesis is dynamic kinetic resolution, dynamic kinetic asymmetric processes and stereoablative transformations. Initially, only enzymes were known to catalyze dynamic kinetic processes but recently various synthetic catalysts have been developed. This review summarizes major advances in non-enzymatic, transition metal promoted dynamic asymmetric transformations reported between 2005 and 2015. PMID:28164696

Carrier transport dynamics in Mn-doped CdSe quantum dot sensitized solar cells

NASA Astrophysics Data System (ADS)

Poudyal, Uma; Maloney, Francis S.; Sapkota, Keshab; Wang, Wenyong

2017-10-01

In this work quantum dot sensitized solar cells (QDSSCs) were fabricated with CdSe and Mn-doped CdSe quantum dots (QDs) using the SILAR method. QDSSCs based on Mn-doped CdSe QDs exhibited improved incident photon-to-electron conversion efficiency. Carrier transport dynamics in the QDSSCs were studied using the intensity modulated photocurrent/photovoltage spectroscopy technique, from which transport and recombination time constants could be derived. Compared to CdSe QDSSCs, Mn-CdSe QDSSCs exhibited shorter transport time constant, longer recombination time constant, longer diffusion length, and higher charge collection efficiency. These observations suggested that Mn doping in CdSe QDs could benefit the performance of solar cells based on such nanostructures.

Application of a solar UV/chlorine advanced oxidation process to oil sands process-affected water remediation.

PubMed

Shu, Zengquan; Li, Chao; Belosevic, Miodrag; Bolton, James R; El-Din, Mohamed Gamal

2014-08-19

The solar UV/chlorine process has emerged as a novel advanced oxidation process for industrial and municipal wastewaters. Currently, its practical application to oil sands process-affected water (OSPW) remediation has been studied to treat fresh OSPW retained in large tailings ponds, which can cause significant adverse environmental impacts on ground and surface waters in Northern Alberta, Canada. Degradation of naphthenic acids (NAs) and fluorophore organic compounds in OSPW was investigated. In a laboratory-scale UV/chlorine treatment, the NAs degradation was clearly structure-dependent and hydroxyl radical-based. In terms of the NAs degradation rate, the raw OSPW (pH ∼ 8.3) rates were higher than those at an alkaline condition (pH = 10). Under actual sunlight, direct solar photolysis partially degraded fluorophore organic compounds, as indicated by the qualitative synchronous fluorescence spectra (SFS) of the OSPW, but did not impact NAs degradation. The solar/chlorine process effectively removed NAs (75-84% removal) and fluorophore organic compounds in OSPW in the presence of 200 or 300 mg L(-1) OCl(-). The acute toxicity of OSPW toward Vibrio fischeri was reduced after the solar/chlorine treatment. However, the OSPW toxicity toward goldfish primary kidney macrophages after solar/chlorine treatment showed no obvious toxicity reduction versus that of untreated OSPW, which warrants further study for process optimization.

Using Real and Simulated TNOs to Constrain the Outer Solar System

NASA Astrophysics Data System (ADS)

Kaib, Nathan

2018-04-01

Over the past 2-3 decades our understanding of the outer solar system’s history and current state has evolved dramatically. An explosion in the number of detected trans-Neptunian objects (TNOs) coupled with simultaneous advances in numerical models of orbital dynamics has driven this rapid evolution. However, successfully constraining the orbital architecture and evolution of the outer solar system requires accurately comparing simulation results with observational datasets. This process is challenging because observed datasets are influenced by orbital discovery biases as well as TNO size and albedo distributions. Meanwhile, such influences are generally absent from numerical results. Here I will review recent work I and others have undertaken using numerical simulations in concert with catalogs of observed TNOs to constrain the outer solar system’s current orbital architecture and past evolution.

Similarity Rules for Scaling Solar Sail Systems

NASA Technical Reports Server (NTRS)

Canfield, Stephen L.; Peddieson, John; Garbe, Gregory

2010-01-01

Future science missions will require solar sails on the order of 200 square meters (or larger). However, ground demonstrations and flight demonstrations must be conducted at significantly smaller sizes, due to limitations of ground-based facilities and cost and availability of flight opportunities. For this reason, the ability to understand the process of scalability, as it applies to solar sail system models and test data, is crucial to the advancement of this technology. This paper will approach the problem of scaling in solar sail models by developing a set of scaling laws or similarity criteria that will provide constraints in the sail design process. These scaling laws establish functional relationships between design parameters of a prototype and model sail that are created at different geometric sizes. This work is applied to a specific solar sail configuration and results in three (four) similarity criteria for static (dynamic) sail models. Further, it is demonstrated that even in the context of unique sail material requirements and gravitational load of earth-bound experiments, it is possible to develop appropriate scaled sail experiments. In the longer term, these scaling laws can be used in the design of scaled experimental tests for solar sails and in analyzing the results from such tests.

Advanced Electric Propulsion for Space Solar Power Satellites

NASA Technical Reports Server (NTRS)

Oleson, Steve

1999-01-01

The sun tower concept of collecting solar energy in space and beaming it down for commercial use will require very affordable in-space as well as earth-to-orbit transportation. Advanced electric propulsion using a 200 kW power and propulsion system added to the sun tower nodes can provide a factor of two reduction in the required number of launch vehicles when compared to in-space cryogenic chemical systems. In addition, the total time required to launch and deliver the complete sun tower system is of the same order of magnitude using high power electric propulsion or cryogenic chemical propulsion: around one year. Advanced electric propulsion can also be used to minimize the stationkeeping propulsion system mass for this unique space platform. 50 to 100 kW class Hall, ion, magnetoplasmadynamic, and pulsed inductive thrusters are compared. High power Hall thruster technology provides the best mix of launches saved and shortest ground to Geosynchronous Earth Orbital Environment (GEO) delivery time of all the systems, including chemical. More detailed studies comparing launch vehicle costs, transfer operations costs, and propulsion system costs and complexities must be made to down-select a technology. The concept of adding electric propulsion to the sun tower nodes was compared to a concept using re-useable electric propulsion tugs for Low Earth Orbital Environment (LEO) to GEO transfer. While the tug concept would reduce the total number of required propulsion systems, more launchers and notably longer LEO to GEO and complete sun tower ground to GEO times would be required. The tugs would also need more complex, longer life propulsion systems and the ability to dock with sun tower nodes.

The Third Solar Wind Conference: A summary

NASA Technical Reports Server (NTRS)

Russell, C. T.

1974-01-01

The Third Solar Wind Conference consisted of nine sessions. The following subjects were discussed: (1) solar abundances; (2) the history and evolution of the solar wind; (3) the structure and dynamics of the solar corona; (4) macroscopic and microscopic properties of the solar wind; (5) cosmic rays as a probe of the solar wind; (6) the structure and dynamics of the solar wind; (7) spatial gradients; (8) stellar winds; and (9) interactions with objects in the solar wind. The invited and contributed talks presented at the conference are summarized.

Refractive Secondary Concentrators for Solar Thermal Applications

NASA Technical Reports Server (NTRS)

Wong, Wayne A.; Macosko, Robert P.

1999-01-01

The NASA Glenn Research Center is developing technologies that utilize solar energy for various space applications including electrical power conversion, thermal propulsion, and furnaces. Common to all of these applications is the need for highly efficient, solar concentration systems. An effort is underway to develop the innovative single crystal refractive secondary concentrator, which uses refraction and total internal reflection to efficiently concentrate and direct solar energy. The refractive secondary offers very high throughput efficiencies (greater than 90%), and when used in combination with advanced primary concentrators, enables very high concentration ratios (10,0(X) to 1) and very high temperatures (greater than 2000 K). Presented is an overview of the refractive secondary concentrator development effort at the NASA Glenn Research Center, including optical design and analysis techniques, thermal modeling capabilities, crystal materials characterization testing, optical coatings evaluation, and component testing. Also presented is a discussion of potential future activity and technical issues yet to be resolved. Much of the work performed to date has been in support of the NASA Marshall Space Flight Center's Solar Thermal Propulsion Program. The many benefits of a refractive secondary concentrator that enable efficient, high temperature thermal propulsion system designs, apply equally well to other solar applications including furnaces and power generation systems such as solar dynamics, concentrated thermal photovoltaics, and thermionics.

Advanced solar-propelled cargo spacecraft for Mars missions

NASA Technical Reports Server (NTRS)

Auziasdeturenne, J.; Beall, M.; Burianek, J.; Cinniger, A.; Dunmire, B.; Haberman, E.; Iwamoto, J.; Johnson, S.; Mccracken, S.; Miller, M.

1989-01-01

At the University of Washington, three concepts for an unmanned, solar powered, cargo spacecraft for Mars-support missions have been investigated. These spacecraft are designed to carry a 50,000 kg payload from a low Earth orbit to a low Mars orbit. Each design uses a distinctly different propulsion system: a solar radiation absorption (SRA) system, a solar-pumped laser (SPL) system, and a solar powered mangetoplasmadynamic (MPD) arc system. The SRA directly converts solar energy to thermal energy in the propellant through a novel process developed at the University of Washington. A solar concentrator focuses sunlight into an absorption chamber. A mixture of hydrogen and potassium vapor absorbs the incident radiation and is heated to approximately 3700 K. The hot propellant gas exhausts through a nozzle to produce thrust. The SRA has an I(sub sp) of approximately 1000 sec and produces a thrust of 2940 N using two thrust chambers. In the SPL system, a pair of solar-pumped, multi-megawatt, CO2 lasers in sun-synchronous Earth orbit converts solar energy to laser energy. The laser beams are transmitted to the spacecraft via laser relay satellites. The laser energy heats the hydrogen propellant through a plasma breakdown process in the center of an absorption chamber. Propellant flowing through the chamber, heated by the plasma core, expands through a nozzle to produce thrust. The SPL has an I(sub sp) of 1285 sec and produces a thrust of 1200 N using two thrust chambers. The MPD system uses indium phosphide solar cells to convert sunlight to electricity, which powers the propulsion system. In this system, the argon propellant is ionized and electromagnetically accelerated by a magnetoplasmadynamic arc to produce thrust. The MPD spacecraft has an I(sub sp) of 2490 sec and produces a thrust of 100 N. Various orbital transfer options are examined for these concepts. In the SRA system, the mother ship transfers the payload into a very high Earth orbit and a small auxiliary

Solar physics in the space age

NASA Technical Reports Server (NTRS)

1989-01-01

A concise and brief review is given of the solar physics' domain, and how its study has been affected by NASA Space programs which have enabled space based observations. The observations have greatly increased the knowledge of solar physics by proving some theories and challenging others. Many questions remain unanswered. To exploit coming opportunities like the Space Station, solar physics must continue its advances in instrument development, observational techniques, and basic theory. Even with the Advance Solar Observatory, other space based observation will still be required for the sure to be ensuing questions.

NASA's SDO Sees a Solar Flare and a Lunar Transit

NASA Image and Video Library

2017-12-08

A solar flare erupts on Jan. 30, 2014, as seen by the bright flash on the left side of the sun, captured here by NASA's Solar Dynamics Observatory. In the lower right corner the moon can be seen, having just passed between the observatory and the sun. --- The sun emitted a mid-level solar flare, peaking at 11:11 a.m. EST on Jan. 30, 2014. Images of the flare were captured by NASA's Solar Dynamics Observatory, or SDO, shortly after the observatory witnessed a lunar transit. The black disk of the moon can be seen in the lower right of the images. Solar flares are powerful bursts of radiation. Harmful radiation from a flare cannot pass through Earth's atmosphere to physically affect humans on the ground, however -- when intense enough -- they can disturb the atmosphere in the layer where GPS and communications signals travel. To see how this event may impact Earth, please visit NOAA's Space Weather Prediction Center at spaceweather.gov, the U.S. government's official source for space weather forecasts, alerts, watches and warnings. This flare is classified as an M6.6 class flare. Updates will be provided as needed. Credit: NASA/SDO NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Solar System evolution from compositional mapping of the asteroid belt.

PubMed

DeMeo, F E; Carry, B

2014-01-30

Advances in the discovery and characterization of asteroids over the past decade have revealed an unanticipated underlying structure that points to a dramatic early history of the inner Solar System. The asteroids in the main asteroid belt have been discovered to be more compositionally diverse with size and distance from the Sun than had previously been known. This implies substantial mixing through processes such as planetary migration and the subsequent dynamical processes.

Evaluation of alternative phase change materials for energy storage in solar dynamic applications

NASA Technical Reports Server (NTRS)

Crane, R. A.; Dustin, M. O.

1988-01-01

The performance of fluoride salt and metallic thermal energy storage materials are compared in terms of basic performance as applied to solar dynamic power generation. Specific performance considerations include uniformity of cycle inlet temperature, peak cavity temperature, TES utilization, and system weights. Also investigated were means of enhancing the thermal conductivity of the salts and its effect on the system performance.

Solar Sail Spaceflight Simulation

NASA Technical Reports Server (NTRS)

Lisano, Michael; Evans, James; Ellis, Jordan; Schimmels, John; Roberts, Timothy; Rios-Reyes, Leonel; Scheeres, Daniel; Bladt, Jeff; Lawrence, Dale; Piggott, Scott

2007-01-01

The Solar Sail Spaceflight Simulation Software (S5) toolkit provides solar-sail designers with an integrated environment for designing optimal solar-sail trajectories, and then studying the attitude dynamics/control, navigation, and trajectory control/correction of sails during realistic mission simulations. Unique features include a high-fidelity solar radiation pressure model suitable for arbitrarily-shaped solar sails, a solar-sail trajectory optimizer, capability to develop solar-sail navigation filter simulations, solar-sail attitude control models, and solar-sail high-fidelity force models.

MERIDIONAL CIRCULATION DYNAMICS FROM 3D MAGNETOHYDRODYNAMIC GLOBAL SIMULATIONS OF SOLAR CONVECTION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Passos, Dário; Charbonneau, Paul; Miesch, Mark, E-mail: dariopassos@ist.utl.pt

The form of solar meridional circulation is a very important ingredient for mean field flux transport dynamo models. However, a shroud of mystery still surrounds this large-scale flow, given that its measurement using current helioseismic techniques is challenging. In this work, we use results from three-dimensional global simulations of solar convection to infer the dynamical behavior of the established meridional circulation. We make a direct comparison between the meridional circulation that arises in these simulations and the latest observations. Based on our results, we argue that there should be an equatorward flow at the base of the convection zone atmore » mid-latitudes, below the current maximum depth helioseismic measures can probe (0.75 R{sub ⊙}). We also provide physical arguments to justify this behavior. The simulations indicate that the meridional circulation undergoes substantial changes in morphology as the magnetic cycle unfolds. We close by discussing the importance of these dynamical changes for current methods of observation which involve long averaging periods of helioseismic data. Also noteworthy is the fact that these topological changes indicate a rich interaction between magnetic fields and plasma flows, which challenges the ubiquitous kinematic approach used in the vast majority of mean field dynamo simulations.« less

High-Order Shock-Capturing Methods for Modeling Dynamics of the Solar Atmosphere

NASA Technical Reports Server (NTRS)

Bryson, Steve; Kosovichev, Alexander; Levy, Doron

2004-01-01

We use one-dimensional high-order central shock capturing numerical methods to study the response of various model solar atmospheres to forcing at the solar surface. The dynamics of the atmosphere is modeled with the Euler equations in a variable-sized flux tube in the presence of gravity. We study dynamics of the atmosphere suggestive of spicule formation and coronal oscillations. These studies are performed on observationally-derived model atmospheres above the quiet sun and above sunspots. To perform these simulations, we provide a new extension of existing second- and third- order shock-capturing methods to irregular grids. We also solve the problem of numerically maintaining initial hydrostatic balance via the introduction of new variables in the model equations and a careful initialization mechanism. We find several striking results: all model atmospheres respond to a single impulsive perturbation with several strong shock waves consistent with the rebound-shock model. These shock waves lift material and the transition region well into the initial corona, and the sensitivity of this lift to the initial impulse depends non-linearly on the details of the atmosphere model. We also reproduce an observed 3-minute coronal oscillation above sunspots compared to 5-minute oscillations above the quiet sun.

Meridional Circulation Dynamics from 3D Magnetohydrodynamic Global Simulations of Solar Convection

NASA Astrophysics Data System (ADS)

Passos, Dário; Charbonneau, Paul; Miesch, Mark

2015-02-01

The form of solar meridional circulation is a very important ingredient for mean field flux transport dynamo models. However, a shroud of mystery still surrounds this large-scale flow, given that its measurement using current helioseismic techniques is challenging. In this work, we use results from three-dimensional global simulations of solar convection to infer the dynamical behavior of the established meridional circulation. We make a direct comparison between the meridional circulation that arises in these simulations and the latest observations. Based on our results, we argue that there should be an equatorward flow at the base of the convection zone at mid-latitudes, below the current maximum depth helioseismic measures can probe (0.75 {{R}⊙ }). We also provide physical arguments to justify this behavior. The simulations indicate that the meridional circulation undergoes substantial changes in morphology as the magnetic cycle unfolds. We close by discussing the importance of these dynamical changes for current methods of observation which involve long averaging periods of helioseismic data. Also noteworthy is the fact that these topological changes indicate a rich interaction between magnetic fields and plasma flows, which challenges the ubiquitous kinematic approach used in the vast majority of mean field dynamo simulations.

Dynamics of the solar wind and its interaction with bodies in the solar system

NASA Technical Reports Server (NTRS)

Spreiter, J. R.

1971-01-01

A discussion of the solar wind and its interaction with bodies of the solar system is presented. An overall unified account of the role of shock waves in the heating of the solar corona, the transmission of solar disturbances to the solar system, the flow fields of planets and natural satellites, and biological effects are provided. An analysis of magnetometer data from Explorer 33 and Vela 3A satellites to identify characteristics of solar wind shock waves is included.

The Focusing Optics X-ray Solar Imager (FOXSI): Instrument and First Flight

NASA Astrophysics Data System (ADS)

Glesener, Lindsay; Christe, S.; Ishikawa, S.; Ramsey, B.; Takahashi, T.; Saito, S.; Lin, R. P.; Krucker, S.; FOXSI Team

2013-04-01

Understanding electron acceleration in solar flares requires hard X-ray studies with greater sensitivity and dynamic range than are available with current solar hard X-ray observers (i.e. the RHESSI spacecraft). Both these capabilities can be advanced by the use of direct focusing optics instead of the indirect Fourier methods of current and previous generations. The Focusing Optics X-ray Solar Imager (FOXSI) sounding rocket payload demonstrates the feasibility and usefulness of hard X-ray focusing optics for solar observation. FOXSI flew for the first time on 2012 November 2, producing images and spectra of a microflare and performing a search for nonthermal X-rays from the quiet Sun. Such measurements are important for characterizing the impact of small "nanoflares" on the solar coronal heating problem. A spaceborne solar observer featuring similar optics could make detailed observations of hard X-rays from flare-accelerated electrons, identifying and characterizing particle acceleration sites and mapping out paths of energetic electrons as they leave these sites and propagate throughout the solar corona. Solar observations from NuSTAR are also expected to be an important step in this direction.

Solar Power System Design for the Solar Probe+ Mission

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.; Schmitz, Paul C.; Kinnison, James; Fraeman, Martin; Roufberg, Lew; Vernon, Steve; Wirzburger, Melissa

2008-01-01

Solar Probe+ is an ambitious mission proposed to the solar corona, designed to make a perihelion approach of 9 solar radii from the surface of the sun. The high temperature, high solar flux environment makes this mission a significant challenge for power system design. This paper summarizes the power system conceptual design for the solar probe mission. Power supplies considered included nuclear, solar thermoelectric generation, solar dynamic generation using Stirling engines, and solar photovoltaic generation. The solar probe mission ranges from a starting distance from the sun of 1 AU, to a minimum distance of about 9.5 solar radii, or 0.044 AU, from the center of the sun. During the mission, the solar intensity ranges from one to about 510 times AM0. This requires power systems that can operate over nearly three orders of magnitude of incident intensity.

The Formation and Evolution of the Solar System

NASA Astrophysics Data System (ADS)

Marov, Mikhail

2018-05-01

The formation and evolution of our solar system (and planetary systems around other stars) are among the most challenging and intriguing fields of modern science. As the product of a long history of cosmic matter evolution, this important branch of astrophysics is referred to as stellar-planetary cosmogony. Interdisciplinary by way of its content, it is based on fundamental theoretical concepts and available observational data on the processes of star formation. Modern observational data on stellar evolution, disc formation, and the discovery of extrasolar planets, as well as mechanical and cosmochemical properties of the solar system, place important constraints on the different scenarios developed, each supporting the basic cosmogony concept (as rooted in the Kant-Laplace hypothesis). Basically, the sequence of events includes fragmentation of an original interstellar molecular cloud, emergence of a primordial nebula, and accretion of a protoplanetary gas-dust disk around a parent star, followed by disk instability and break-up into primary solid bodies (planetesimals) and their collisional interactions, eventually forming a planet. Recent decades have seen major advances in the field, due to in-depth theoretical and experimental studies. Such advances have clarified a new scenario, which largely supports simultaneous stellar-planetary formation. Here, the collapse of a protosolar nebula's inner core gives rise to fusion ignition and star birth with an accretion disc left behind: its continuing evolution resulting ultimately in protoplanets and planetary formation. Astronomical observations have allowed us to resolve in great detail the turbulent structure of gas-dust disks and their dynamics in regard to solar system origin. Indeed radio isotope dating of chondrite meteorite samples has charted the age and the chronology of key processes in the formation of the solar system. Significant progress also has been made in the theoretical study and computer modeling

An IRIS Optically Thin View of the Dynamics of the Solar Chromosphere

NASA Astrophysics Data System (ADS)

Carlsson, M.

2017-12-01

We analyze the formation of the O I 1356 and Cl I 1351 lines and show that they are formed in the mid-chromosphere and are optically thin. Their non-thermal line-widths are thus a direct measure of the velocity field along the line of sight. We use this insight to analyze a large set of observations from the Interface Region Imaging Spectrograph (IRIS) to study the dynamics of the Solar Chromosphere.

Advanced light-trapping effect of thin-film solar cell with dual photonic crystals

NASA Astrophysics Data System (ADS)

Zhang, Anjun; Guo, Zhongyi; Tao, Yifei; Wang, Wei; Mao, Xiaoqin; Fan, Guanghua; Zhou, Keya; Qu, Shiliang

2015-05-01

A thin-film solar cell with dual photonic crystals has been proposed, which shows an advanced light-trapping effect and superior performance in ultimate conversion efficiency (UCE). The shapes of nanocones have been optimized and discussed in detail by self-definition. The optimized shape of nanocone arrays (NCs) is a parabolic shape with a nearly linearly graded refractive index (GRI) profile from the air to Si, and the corresponding UCE is 30.3% for the NCs with a period of 300 nm and a thickness of only 2 μm. The top NCs and bottom NCs of the thin film have been simulated respectively to investigate their optimized shapes, and their separate contributions to the light harvest have also been discussed fully. The height of the top NCs and bottom NCs will also influence the performances of the thin-film solar cell greatly, and the result indicates that the unconformal NCs have better light-trapping ability with an optimal UCE of 32.3% than the conformal NCs with an optimal UCE of 30.3%.

Variations of solar, interplanetary, and geomagnetic parameters with solar magnetic multipole fields during Solar Cycles 21-24

NASA Astrophysics Data System (ADS)

Kim, Bogyeong; Lee, Jeongwoo; Yi, Yu; Oh, Suyeon

2015-01-01

In this study we compare the temporal variations of the solar, interplanetary, and geomagnetic (SIG) parameters with that of open solar magnetic flux from 1976 to 2012 (from Solar Cycle 21 to the early phase of Cycle 24) for a purpose of identifying their possible relationships. By the open flux, we mean the average magnetic field over the source surface (2.5 solar radii) times the source area as defined by the potential field source surface (PFSS) model of the Wilcox Solar Observatory (WSO). In our result, most SIG parameters except the solar wind dynamic pressure show rather poor correlations with the open solar magnetic field. Good correlations are recovered when the contributions from individual multipole components are counted separately. As expected, solar activity indices such as sunspot number, total solar irradiance, 10.7 cm radio flux, and solar flare occurrence are highly correlated with the flux of magnetic quadrupole component. The dynamic pressure of solar wind is strongly correlated with the dipole flux, which is in anti-phase with Solar Cycle (SC). The geomagnetic activity represented by the Ap index is correlated with higher order multipole components, which show relatively a slow time variation with SC. We also found that the unusually low geomagnetic activity during SC 23 is accompanied by the weak open solar fields compared with those in other SCs. It is argued that such dependences of the SIG parameters on the individual multipole components of the open solar magnetic flux may clarify why some SIG parameters vary in phase with SC and others show seemingly delayed responses to SC variation.

Wave heating of the solar atmosphere

NASA Astrophysics Data System (ADS)

Arregui, Iñigo

2015-04-01

Magnetic waves are a relevant component in the dynamics of the solar atmosphere. Their significance has increased because of their potential as a remote diagnostic tool and their presumed contribution to plasma heating processes. We discuss our current understanding of coronal heating by magnetic waves, based on recent observational evidence and theoretical advances. The discussion starts with a selection of observational discoveries that have brought magnetic waves to the forefront of the coronal heating discussion. Then, our theoretical understanding of the nature and properties of the observed waves and the physical processes that have been proposed to explain observations are described. Particular attention is given to the sequence of processes that link observed wave characteristics with concealed energy transport, dissipation and heat conversion. We conclude with a commentary on how the combination of theory and observations should help us to understand and quantify magnetic wave heating of the solar atmosphere.

Update of the 2 Kw Solar Dynamic Ground Test Demonstration Program

NASA Technical Reports Server (NTRS)

Shaltens, Richard K.; Boyle, Robert V.

1994-01-01

The Solar Dynamic (SD) Ground Test Demonstration (GTD) program demonstrates the operation of a complete 2 kW, SD system in a simulated space environment at a NASA Lewis Research Center (LeRC) thermal-vacuum facility. This paper reviews the goals and status of the SD GTD program. A brief description of the SD system identifying key design features of the system, subsystems, and components is included. An aerospace industry/government team is working together to design, fabricate, assemble, and test a complete SD system.

A dynamical model of plasma turbulence in the solar wind

PubMed Central

Howes, G. G.

2015-01-01

A dynamical approach, rather than the usual statistical approach, is taken to explore the physical mechanisms underlying the nonlinear transfer of energy, the damping of the turbulent fluctuations, and the development of coherent structures in kinetic plasma turbulence. It is argued that the linear and nonlinear dynamics of Alfvén waves are responsible, at a very fundamental level, for some of the key qualitative features of plasma turbulence that distinguish it from hydrodynamic turbulence, including the anisotropic cascade of energy and the development of current sheets at small scales. The first dynamical model of kinetic turbulence in the weakly collisional solar wind plasma that combines self-consistently the physics of Alfvén waves with the development of small-scale current sheets is presented and its physical implications are discussed. This model leads to a simplified perspective on the nature of turbulence in a weakly collisional plasma: the nonlinear interactions responsible for the turbulent cascade of energy and the formation of current sheets are essentially fluid in nature, while the collisionless damping of the turbulent fluctuations and the energy injection by kinetic instabilities are essentially kinetic in nature. PMID:25848075

Simultaneous disappearances of plasmaspheric hiss, exohiss, and chorus waves triggered by a sudden decrease in solar wind dynamic pressure

DOE PAGES

Liu, Nigang; Su, Zhenpeng; Gao, Zhonglei; ...

2016-12-29

Magnetospheric whistler mode waves are of great importance in the radiation belt electron dynamics. In this paper, on the basis of the analysis of a rare event with the simultaneous disappearances of whistler mode plasmaspheric hiss, exohiss, and chorus triggered by a sudden decrease in the solar wind dynamic pressure, we provide evidences for the following physical scenarios: (1) nonlinear generation of chorus controlled by the geomagnetic field inhomogeneity, (2) origination of plasmaspheric hiss from chorus, and (3) leakage of plasmaspheric hiss into exohiss. Finally, following the reduction of the solar wind dynamic pressure, the dayside geomagnetic field configuration withmore » the enhanced inhomogeneity became unfavorable for the generation of chorus, and the quenching of chorus directly caused the disappearances of plasmaspheric hiss and then exohiss.« less

Simultaneous disappearances of plasmaspheric hiss, exohiss, and chorus waves triggered by a sudden decrease in solar wind dynamic pressure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Nigang; Su, Zhenpeng; Gao, Zhonglei

Magnetospheric whistler mode waves are of great importance in the radiation belt electron dynamics. In this paper, on the basis of the analysis of a rare event with the simultaneous disappearances of whistler mode plasmaspheric hiss, exohiss, and chorus triggered by a sudden decrease in the solar wind dynamic pressure, we provide evidences for the following physical scenarios: (1) nonlinear generation of chorus controlled by the geomagnetic field inhomogeneity, (2) origination of plasmaspheric hiss from chorus, and (3) leakage of plasmaspheric hiss into exohiss. Finally, following the reduction of the solar wind dynamic pressure, the dayside geomagnetic field configuration withmore » the enhanced inhomogeneity became unfavorable for the generation of chorus, and the quenching of chorus directly caused the disappearances of plasmaspheric hiss and then exohiss.« less

Advanced Solar Cell Testing and Characterization

NASA Technical Reports Server (NTRS)

Bailey, Sheila; Curtis, Henry; Piszczor, Michael

2005-01-01

The topic for this workshop stems from an ongoing effort by the photovoltaic community and U.S. government to address issues and recent problems associated with solar cells and arrays experienced by a number of different space systems. In April 2003, a workshop session was held at the Aerospace Space Power Workshop to discuss an effort by the Air Force to update and standardize solar cell and array qualification test procedures in an effort to ameliorate some of these problems. The organizers of that workshop session thought it was important to continue these discussions and present this information to the entire photovoltaic community. Thus, it was decided to include this topic as a workshop at the following SPRAT conference.

Solar electric propulsion thruster interactions with solar arrays

NASA Technical Reports Server (NTRS)

Parks, D. E.; Katz, I.

1977-01-01

The effect of interactions of spacecraft-generated and naturally occurring plasmas with high voltage solar array components on an advanced solar electric propulsion system proposed for the Halley's Comet rendezvous mission was investigated. The spacecraft-generated plasma consists of mercury ions and neutralizing electrons resulting from the operation of ion thrusters (the charge-exchange plasma) and associated hollow cathode neutralizers. Quantitative results are given for the parasitic currents and power coupled into solar arrays with voltage fixed as a function of position on the array.

Modeling Study of the Geospace System Response to the Solar Wind Dynamic Pressure Enhancement on 17 March 2015

NASA Astrophysics Data System (ADS)

Ozturk, D. S.; Zou, S.; Ridley, A. J.; Slavin, J. A.

2018-04-01

The global magnetosphere-ionosphere-thermosphere system is intrinsically coupled and susceptible to external drivers such as solar wind dynamic pressure enhancements. In order to understand the large-scale dynamic processes in the magnetosphere-ionosphere-thermosphere system due to the compression from the solar wind, the 17 March 2015 sudden commencement was studied in detail using global numerical models. This storm was one of the most geoeffective events of the solar cycle 24 with a minimum Dst of -222 nT. The Wind spacecraft recorded a 10-nPa increment in the solar wind dynamic pressure, while the interplanetary magnetic field BZ became further northward. The University of Michigan Block-Adaptive-Tree Solar wind Roe-type Upwind Scheme global magnetohydrodynamic code was utilized to study the generation and propagation of perturbations associated with the compression of the magnetosphere system. In addition, the high-resolution electric potential and auroral power output from the magnetohydrodynamic model was used to drive the global ionosphere-thermosphere model to investigate the ionosphere-thermosphere system response to pressure enhancement. During the compression, the electric potentials and convection patterns in the polar ionosphere were significantly altered when the preliminary impulse and main impulse field-aligned currents moved from dayside to nightside. As a result of enhanced frictional heating, plasma and neutral temperatures increased at the locations where the flow speeds were enhanced, whereas the electron density dropped at these locations. In particular, the region between the preliminary impulse and main impulse field-aligned currents experienced the most significant heating with 1000-K ion temperature increase and 20-K neutral temperature increase within 2 min. Comparison of the simulation results with the Poker Flat Incoherent Scatter Radar observations showed reasonable agreements despite underestimated magnitudes.

Solar Job Related Training.

ERIC Educational Resources Information Center

Lennox Industries, Inc., Dallas, TX.

This book contains comprehensive instruction in design, installation, and service procedures for typical solar space heat and domestic hot water systems. The book is comprised of five major sections. Solar Systems: Past and Present presents a brief look at how far solar technology has advanced. Included in this section are descriptions of over…

Research progress on organic-inorganic halide perovskite materials and solar cells

NASA Astrophysics Data System (ADS)

Ono, Luis K.; Qi, Yabing

2018-03-01

Owing to the intensive research efforts across the world since 2009, perovskite solar cell power conversion efficiencies (PCEs) are now comparable or even better than several other photovoltaic (PV) technologies. In this topical review article, we review recent progress in the field of organic-inorganic halide perovskite materials and solar cells. We associate these achievements with the fundamental knowledge gained in the perovskite research. The major recent advances in the fundamental perovskite material and solar cell research are highlighted, including the current efforts in visualizing the dynamical processes (in operando) taking place within a perovskite solar cell under operating conditions. We also discuss the existing technological challenges. Based on a survey of recently published works, we point out that to move the perovskite PV technology forward towards the next step of commercialization, what perovskite PV technology need the most in the coming next few years is not only further PCE enhancements, but also up-scaling, stability, and lead-toxicity.

Some operational aspects of a rotating advanced-technology space station for the year 2025

NASA Technical Reports Server (NTRS)

Queijo, M. J.; Butterfield, A. J.; Cuddihy, W. F.; King, C. B.; Stone, R. W.; Wrobel, J. R.; Garn, P. A.

1988-01-01

The study of an Advanced Technology Space Station which would utilize the capabilities of subsystems projected for the time frame of the years 2000 to 2025 is discussed. The study includes tradeoffs of nuclear versus solar dynamic power systems that produce power outputs of 2.5 megawatts and analyses of the dynamics of the spacecraft of which portions are rotated for artificial gravity. The design considerations for the support of a manned Mars mission from low Earth orbit are addressed. The studies extend to on-board manufacturing, internal gas composition effects, and locomotion and material transfer under artificial gravity forces. The report concludes with an assessment of technology requirements for the Advanced Technology Space Station.

Newman Unit 1 advanced solar repowering advanced conceptual design. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1982-04-01

The Newman Unit 1 solar repowering design is a water/steam central receiver concept supplying superheated steam. The work reported is to develop a refined baseline conceptual design that has potential for construction and operation by 1986, makes use of existing solar thermal technology, and provides the best economics for this application. Trade studies performed in the design effort are described, both for the conceptual design of the overall system and for the subsystem conceptual design. System-level functional requirements, design, operation, performance, cost, safety, environmental, institutional, and regulatory considerations are described. Subsystems described include the collector, receiver, fossil energy, electrical powermore » generating, and master control subsystems, site and site facilities. The conceptual design, cost, and performance of each subsystem is discussed at length. A detailed economic analysis of the repowered unit is made to realistically assess the economics of the first repowered unit using present cost data for a limited production level for solar hardware. Finally, a development plan is given, including the design, procurement, construction, checkout, startup, performance validation, and commercial operation. (LEW)« less

Observations of the Dynamics and Thermodynamics of the Corona during the 21 August 2017 Total Solar Eclipse

NASA Astrophysics Data System (ADS)

Habbal, Shadia Rifai; Ding, Adalbert; Druckmuller, Miloslav; Solar Wind Sherpas

2018-01-01

The visible wavelength range, encompassing forbidden coronal emission lines, offers unique diagnostic tools for exploring the physics of the solar corona, such as its chemical composition and the dynamics of its major and minor constituents. These tools are best exploited during total solar eclipses, when the field of view spans several solar radii, starting from the solar surface. This spatial span is currently untenable from any observing platform. Imaging and spectroscopic eclipse observations, including the 2017 August 21 event, are shown to be the first to yield the temperature distribution in the corona as a function of solar cycle. They are also the first to lead to the discovery of cool prominence material at less than 10,000 to 50,000 K, within more than a radius above the solar surface, streaming away from the Sun, while maintaining its compositional identity. These data underscore the importance of capturing emission from coronal forbidden lines with the next generation space-based instrumentation to address the general problem of coronal heating.

A compact Dopplergraph/magnetograph suitable for space-based measurements of solar oscillations and magnetic fields

NASA Technical Reports Server (NTRS)

Rhodes, E. J., Jr.; Cacciani, A.; Tomczyk, S.; Ulrich, R. K.; Blamont, J.; Howard, R. F.; Dumont, P.; Smith, E. J.

1984-01-01

A compact Dopplergraph/magnetograph placed in a continuous solar-viewing orbit will allow us to make major advancements in our understanding of solar internal structure and dynamics. An international program is currently being conducted at JPL and Mt. Wilson to develop such an instrument. By combining a unique magneto-optical resonance filter with CID and CCD cameras we have been able to obtain full- and partial-disk Dopplergrams and magnetograms. Time series of the velocity images are converted into k-omega power spectra which show clear- the solar nonradial p-mode oscilations. Magnetograms suitable for studying the long-term evolution of solar active regions have also been obtained with this instrument. A flight instrument based on this concept is being studied for possible inclusion in the SOHO mission.

Non-Extensive Statistical Analysis of Solar Wind Electric, Magnetic Fields and Solar Energetic Particle time series.

NASA Astrophysics Data System (ADS)

Pavlos, G. P.; Malandraki, O.; Khabarova, O.; Livadiotis, G.; Pavlos, E.; Karakatsanis, L. P.; Iliopoulos, A. C.; Parisis, K.

2017-12-01

In this work we study the non-extensivity of Solar Wind space plasma by using electric-magnetic field data obtained by in situ spacecraft observations at different dynamical states of solar wind system especially in interplanetary coronal mass ejections (ICMEs), Interplanetary shocks, magnetic islands, or near the Earth Bow shock. Especially, we study the energetic particle non extensive fractional acceleration mechanism producing kappa distributions as well as the intermittent turbulence mechanism producing multifractal structures related with the Tsallis q-entropy principle. We present some new and significant results concerning the dynamics of ICMEs observed in the near Earth at L1 solar wind environment, as well as its effect in Earth's magnetosphere as well as magnetic islands. In-situ measurements of energetic particles at L1 are analyzed, in response to major solar eruptive events at the Sun (intense flares, fast CMEs). The statistical characteristics are obtained and compared for the Solar Energetic Particles (SEPs) originating at the Sun, the energetic particle enhancements associated with local acceleration during the CME-driven shock passage over the spacecraft (Energetic Particle Enhancements, ESPs) as well as the energetic particle signatures observed during the passage of the ICME. The results are referred to Tsallis non-extensive statistics and in particular to the estimation of Tsallis q-triplet, (qstat, qsen, qrel) of electric-magnetic field and the kappa distributions of solar energetic particles time series of the ICME, magnetic islands, resulting from the solar eruptive activity or the internal Solar Wind dynamics. Our results reveal significant differences in statistical and dynamical features, indicating important variations of the magnetic field dynamics both in time and space domains during the shock event, in terms of rate of entropy production, relaxation dynamics and non-equilibrium meta-stable stationary states.

Supergranulation and multiscale flows in the solar photosphere. Global observations vs. a theory of anisotropic turbulent convection

NASA Astrophysics Data System (ADS)

Rincon, F.; Roudier, T.; Schekochihin, A. A.; Rieutord, M.

2017-03-01

The Sun provides us with the only spatially well-resolved astrophysical example of turbulent thermal convection. While various aspects of solar photospheric turbulence, such as granulation (one-Megameter horizontal scale), are well understood, the questions of the physical origin and dynamical organization of larger-scale flows, such as the 30-Megameters supergranulation and flows deep in the solar convection zone, remain largely open in spite of their importance for solar dynamics and magnetism. Here, we present a new critical global observational characterization of multiscale photospheric flows and subsequently formulate an anisotropic extension of the Bolgiano-Obukhov theory of hydrodynamic stratified turbulence that may explain several of their distinctive dynamical properties. Our combined analysis suggests that photospheric flows in the horizontal range of scales between supergranulation and granulation have a typical vertical correlation scale of 2.5 to 4 Megameters and operate in a strongly anisotropic, self-similar, nonlinear, buoyant dynamical regime. While the theory remains speculative at this stage, it lends itself to quantitative comparisons with future high-resolution acoustic tomography of subsurface layers and advanced numerical models. Such a validation exercise may also lead to new insights into the asymptotic dynamical regimes in which other, unresolved turbulent anisotropic astrophysical fluid systems supporting waves or instabilities operate.

Recent results from advanced research on space solar cells at NASA

NASA Technical Reports Server (NTRS)

Flood, Dennis J.

1990-01-01

The NASA program in space photovoltaic research and development encompasses a wide range of emerging options for future space power systems, and includes both cell and array technology development. The long range goals are to develop technology capable of achieving 300 W/kg for planar arrays, and 300 W/sq m for concentrator arrays. InP and GaAs planar and concentrator cell technologies are under investigation for their potential high efficiency and good radiation resistance. The Advanced Photovoltaic Solar Array (APSA) program is a near term effort aimed at demonstrating 130 W/kg beginning of life specific power using thin (62 pm) silicon cells. It is intended to be technology transparent to future high efficiency cells and provides the baseline for development of the 300 W/kg array.

INTERNAL DYNAMICS OF A TWIN-LAYER SOLAR PROMINENCE