Fluorine Tuning of Morphology, Energy Loss, and Carrier Dynamics in Perylenediimide Polymer Solar Cells
Abstract not provided
Zhu, Weigang↗
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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Modeling of a Networked Community Microgrid with High Solar Penetration Considering Control Dynamics of Inverter-Based Resources
Microgrids help facilitate the integration of renewable energy in distribution-level grids and increase the resilience of the electric grid to extreme weather, especially in rural areas. Compared to traditional microgrids, a networked microgrid leverages multiple grid-forming sources to form a potential meshed grid and is more flexible in operation. This paper demonstrates the simulation modeling of an actual networked microgrid located in Adjuntas, Puerto Rico. The model contains representations of power inverters that connect the battery energy storage systems and photovoltaic generation systems to the networked microgrid and is capable of simulating fast grid transients as well as long-term operation of the networked microgrid. The modeling technique for power inverters allows the time-efficient simulation of the microgrid with a minimal penalty on model accuracy.
Li, Dingrui↗
Spatio-temporal dynamic clustering modeling for solar irradiance resource assessment
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Patricia Maldonado-Salguero↗
A theory of thermosphere dynamics. I - Diurnal and solar cycle variations.
Diurnal and solar cycle variations of thermosphere density and temperature generated by solar EUV input and tidal wave, using two dimensional model
Volland, H.↗
The Third Solar Wind Conference: A summary
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.
Russell, C. T.↗
Dynamical response of the solar corona. III - Numerical simulation of the 1973 June 10 coronal transient
A spherically symmetric adiabatic single-fluid model is outlined for simulating the nonlinear time-dependent response of the corona to solar events that are simulated by perturbations in the appropriate physical variables from their steady-state values at the coronal base. Several observed features of the coronal transient that occurred on June 10, 1973, are simulated by using a particular steady-state solar wind, a specific combination of density and temperature perturbations, and a particular time dependence of the perturbations. A different steady-state solar wind, a perturbation of shorter duration, and other perturbation combinations are also employed to simulate the same transient so that the effect of each quantity can be determined. It is found that the model cannot adequately simulate all the observational results for the investigated transient, that the steady-state solar wind is relatively unimportant in such numerical simulations, and that studies which attempt only to reproduce observed shock trajectories may lead to erroneous conclusions regarding the physics of the solar event that produced the transient.
Steinolfson, R. S.↗
Dynamic MHD modeling of solar wind corotating stream interaction regions observed by Pioneer 10 and 11
The use of the Pioneer 10 and 11 projects to test an MHD one-dimensional time-dependent model of corotating solar wind streams during the period from Sept. 30 to Nov. 25, 1973 is described. During this period, five or six corotating interaction regions streamed past the two spacecraft, and, as a result of multiple-spacecraft radial alignment and temporally varying conditions at the solar wind source, the pattern predicted by the Steinolfson et al. (1975) model could be compared with observations. The results, in general, support the validity of the model, although the neglect of thermal energy exchange leads to incorrect values for the proton temperature. A detailed analysis of a stream is discussed.
Dryer, M.↗
The dynamical properties of the solar corona from intensities and line widths of EUV forbidden lines of Si VIII, Fe XI, and Fe XII
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Cheng, C.-C.↗
A dynamic model for the solar transition region
A model is developed for the lower transition region that can account for the persistent and ubiquitous redshifts that are observed in the UV emission lines formed at these temperatures. It is shown that these shifts are not likely to be due either to falling spicular material or to steady-state siphon flows. The model consists of two key ingredients. The redshifted radiation originates from a minority of flux tubes which have higher gas pressures than their surroundings, and consequently have their transition regions situated below the transition regions of their surroundings. The coronal heating in these loops is impulsive in nature, and this is responsible for the transient mass flows. The studies, therefore, favor theories for coronal heating which involve flare-like magnetic-energy release. Previously announced in STAR as N83-29163
Antiochos, S. K.↗
Energetics and dynamics in a large solar flare of 1989 March
Solar Maximum Mission X-ray observations and National Solar Observatory/Sacramento Peak H alpha spectra are combined in a large (X1.2) solar flare to test predictions of chromospheric heating and evaporation by nonthermal thick-target electrons. It is demonstrated that the ratio of H alpha flare energy flux to the energy flux deposited by thick-target electrons obeys a power-law dependence on electron heating flux, with a slope that is consistent with that predicted by a thick-target electron transport and heating model in a 1D hydrostatic atmosphere. It is concluded that the thick-target model satisfactorily accounts for the observed magnitude of chromospheric H alpha emission, and the amplitudes and timing of oppositely directed plasma motions during the impulsive phase of this X flare.
Wulser, Jean-Pierre↗
Dynamic modeling of the solar atmosphere
A brief review is presented of work done over the last eight years investigating the fundamental physics of plasmas and magnetic fields under conditions similar to those that are thought to be present in the outer layers of the solar atmosphere, including the transition region and the corona. The models used to study the coronal structures and the thermal instability in the solar atmosphere are discussed. The results of studies of magnetic energy release in the corona and MHD turbulence in the solar wind are examined.
Mariska, J. T.↗
Chromospheric dynamics based on infrared solar brightness variations
The NASA Kuiper Airborne Observatory was used to observe far-infrared continuum brightness fluctuations in the lower chromosphere due to solar 5 minute oscillations on the quiet sun. Brightness measurements made at 50, 100, 200, and 400 microns show a strong correlation with visible-line Doppler measurements from photospheric and chromospheric altitudes. The motion of the chromosphere is nearly in phase over a large range of heights, while the infrared brightness lags the Doppler velocity by phases varying from significantly less than 90 deg at low altitudes to nearly 90 deg at higher altitudes. It is proposed that this is the result of a nonadiabatic response of the chromospheric gas to compression and may indicate an important mechanism for wave dissipation. Thermal relaxation times ranging from about 40 s at 340 km above the tau(5000) = 1 photosphere to about 300 s at 600 km are proposed.
Kopp, G.↗
The role of SLR and LLR in relativity
While General Relativity has been adopted as the standard theory of relativity, there are alternative theories, with important implications for gravitational physics, which can only be discounted with tests of sufficient accuracy. In addition to its contributions to lunar and solar system dynamics, Lunar Laser Ranging, in combination with other solar system data continues to refine some important limits. Satellite laser ranging tracking of geodetic satellites can provide similar tests, but the accuracy is usually limited by gravitational and nongravitational perturbations.
Ries, John C.↗
Dynamical Models of the Solar System Formation and Evolution
Mark Lewis has extended his them is work by completing a series of N-body simulations of a narrow ring that: is in the location of Saturn's F-ring and is perturbed by a single satellite comparable to Prometheus, but on a circular orbit. We had previously shown how the satellite perturbations can cause a broadly distributed sparse population of ring particles to become concentrated into narrow rings that can be maintained outside of any resonance location. For low optical depths, the collisions between ring particles are highly localized in the peaks of the satellite wakes. The inelastic collisions therefore occur at a particular orbital phase angle so as to damp the azimuthal component of the relative velocities. Since particle positions are not changed by collisions, the semimajor axes of the particles are shifted toward the actual particle positions where the collisions occur. Thus, negative radial diffusion can occur while conserving orbital angular momentum so long as the forced eccentricity is continually re-excited by the satellite. We speculated that the separation between the final ringlets was largely determined by the magnitude of the forced eccentricities induced by the satellite at closest approach. We carried out a series of simulations with a variety of different satellite masses in order to vary the magnitude of the forced eccentricity. We found that indeed the final spacing of the ringlets does increase with the magnitude of the forced eccentricity (Lewis and Stewart 2002). This occurs because neighboring eccentric ringlets drift out of phase with one another due to Keplerian shear and eventually collide with one another, leading to a smaller number of more widely spaced ringlets, The time scale required to form narrow ringlets in these simulations is much shorter than one would expect from standard theories based upon the orbit-averaged torque produced by multiple passes by the satellite. We find that the initial ringlets form in less than two synodic periods and the final state is typically reached in 10 to 20 synodic periods. These studies move us closer to understanding the significantly more complex system of Saturn's F ring, where the perturbation magnitude varies over short temporal and spatial time scales due to the orbital eccentricities of the perturbing satellite. We are currently extending the simulation to allow for an eccentric orbit of the satellite.
Stewart, Glen R.↗
Dynamic Aperture-based Solar Loop Segmentation
A new method to automatically segment arc-like loop structures from intensity images of the Sun's corona is introduced. The method constructively segments credible loop structures by exploiting the Gaussian-like shape of loop cross-sectional intensity profiles. The experimental results show that the method reasonably segments most of the well-defined loops in coronal images. The method is only the second published automated solar loop segmentation method. Its advantage over the other published method is that it operates independently of supplemental time specific data.
Lee, Jon Kwan↗
Statistical Mechanics and Dynamics of the Outer Solar System.I. The Jupiter/Saturn Zone
We report on numerical simulations designed to understand how the solar system evolved through a winnowing of planetesimals accreeted from the early solar nebula. This sorting process is driven by the energy and angular momentum and continues to the present day. We reconsider the existence and importance of stable niches in the Jupiter/Saturn Zone using greatly improved numerical techniques based on high-order optimized multi-step integration schemes coupled to roundoff error minimizing methods.
numerical simulations planetesimals planet formati↗
Attitude Dynamics and Control of Solar Sails with Articulated Vanes
In this paper we develop a robust nonlinear algorithm for the attitude control of a solar sailcraft with M single degree-of-freedom articulated control vanes. A general attitude controller that tracks an admissible trajectory while rejecting disturbances such as torques due to center-of-mass to center-of-pressure offsets is applied to this problem. We then describe a methodology based on nonlinear programming to allocate the required control torques among the control vanes. A simplified allocation strategy is then applied to a solar sail with four articulated control vanes, and simulation results are given. The performance of the control algorithm and possible limitations of vane-only control are then discussed.
solar sails↗
Space Solar Power Multi-body Dynamics and Controls, Concepts for the Integrated Symmetrical Concentrator Configuration
Orbiting space solar power systems are currently being investigated for possible flight in the time frame of 2015-2020 and later. Such space solar power (SSP) satellites are required to be extremely large in order to make practical the process of collection, conversion to microwave radiation, and reconversion to electrical power at earth stations or at remote locations in space. These large structures are expected to be very flexible presenting unique problems associated with their dynamics and control. The purpose of this project is to apply the expanded TREETOPS multi-body dynamics analysis computer simulation program (with expanded capabilities developed in the previous activity) to investigate the control problems associated with the integrated symmetrical concentrator (ISC) conceptual SSP system. SSP satellites are, as noted, large orbital systems having many bodies (perhaps hundreds) with flexible arrays operating in an orbiting environment where the non-uniform gravitational forces may be the major load producers on the structure so that a high fidelity gravity model is required. The current activity arises from our NRA8-23 SERT proposal. Funding, as a supplemental selection, has been provided by NASA with reduced scope from that originally proposed.
Glaese, John R.↗