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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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This report describes the goal of this project which is to understand how high-energy protons enter the geomagnetic field and arrive at GPS satellites.
The main objective of the LDRD-DR SHIELDS project is to develop a new capability to understand, model, and predict the spacecraft Surface Charging Environment (SCE)
The CXD provides good quality proton flux measurements across a range of proton energies. The data within the 1 st and 3 rd quartile range of the ratio of integral flux values is within 20 – 40%. While proton response of the CXD extends down to 6 MeV due to collimator holes in instrument filters, the > 10 MeV integral proton flux is not well captured as shown by the comparisons with EPS. We recommend that users of the data restrict their analysis to proton energies > 20 MeV. Although the full dataset is available now [https://www.ngdc.noaa.gov/stp/spaceweather/satellite-data/satellite-systems/gps/] this updated flux calculation is not present and so a reprocessing will commence soon and the dataset updated. These calibrated datasets will allow a number of exciting multipoint analyses such as more accurate probing of geomagnetic cutoffs as well as providing additional input to radiation belt climatology models such as AE9/AP9/SPM [Ginet et al., 2013].
This report captures the outputs from the AE9 for the electron environment at geostationary orbit. There is no new work, simply a collection of model outputs to make them easier to use and tailored to quick data gathering for geostationary orbit studies. Other models do exist, such as POLE, but a comprehensive look at each is beyond the scope of this work. Other resources are contained in the references.
Overall Point: Once a radiation belt event has begun, how intense will it be and how long will it last?
Recent advancements in the self-consistent modeling of the plasma and fields in the inner magnetosphere; Challenges facing model development and use for space weather prediction.
We have taken major steps toward developing the tools necessary to explore with unprecedented resolution the plasma structure and dynamics of the Sun-interstellar medium (ISM) interaction region, known as the heliosheath. We have applied a rigorous imaging technique known as Generalized Ridge Regression (GRR) to construct statistically robust sky maps of hydrogen energetic neutral atoms (ENAs) emanating from this region and detected by the Los Alamos-led IBEX-Hi ENA imager [1] on NASA’s Interstellar Boundary Explorer (IBEX) mission [2]. Our methods go far beyond the map reconstruction process currently applied by the IBEX Science Operations Center (ISOC), opening up the possibility of new discovery science with the IBEX data set and positioning LANL for a lead science role for the upcoming Interstellar Mapping and Acceleration Probe (IMAP) mission [3] for which LANL is providing two key experiments. We have successfully demonstrated that the new maps are higher resolution and are capable of revealing structures that are not presently resolveable in standard ISOC maps
Abstract not provided.
One of the main goals of this project to understand the origin of density fluctuations in the solar winds, as revealed by the NASA’s Flagship satellite Parker Solar Probe (PSP) measurements, which motivates us to simulate and analyze magnetohydrodynamic (MHD) turbulence in the compressible regime. To achieve this goal, we have developed a set of sophisticated turbulence driving methods to study how MHD turbulence will develop under different time-correlated fluctuations at large-scales. Another key advance is that we have developed a new 3+1 (three spatial plus time domain) 4D FFT analysis of simulation data-cubes so that we can perform the spatio-temporal spectrum and mode decomposition studies on MHD turbulence.
Abstract not provided.
Determine the effectiveness of using electron strahl temperature to infer coronal source temperature. Suprathermal electron strahl temperature derived from measurements at 1 AU does retain information regarding the coronal source temperature from which it originates. This correlation is most strongly measured during the leading edges of coronal hole events but is generally also present in full event measurements. This correlation is also observed in CME events during a coronal hole.
Solar energetic particles are high-energy charged particles accelerated by solar flares and coronal mass ejections (CMEs).
Heliophysics theory and modeling build understanding from fundamental principles to motivate, interpret, and predict observations. Together with observational analysis, they constitute a comprehensive scientific program in heliophysics. As observations and data analysis become increasingly detailed, it is critical that theory and modeling develop more quantitative predictions and iterate with observations. Advanced theory and modeling can inspire and greatly improve the design of new instruments and increase their chance of success. In addition, in order to build physicsbased space weather forecast models, it is important to keep developing and testing new theories, and maintaining constant communications with theory and modeling. Maintaining a sustainable effort in theory and modeling is critically important to heliophysics. We recommend that all funding agencies join forces and consider expanding current and creating new theory and modeling programs–especially, 1. NASA should restore the HTMS program to its original support level to meet the critical needs of heliophysics science; 2. a Strategic Research Model program needs to be created to support model development for next-generation basic research codes; 3. new programs must be created for addressing mission-critical theory and modeling needs; and 4. enhanced programs are urgently required for training the next generation of theorists and modelers.
Abstract not provided.
Three problems with the historical literature were discussed. Kennel and Engelmann (1966): ‘notational error’ that implies that diffusion coefficients depend on the distribution of wave power with respect to ψ. This dependence is unphysical and is not present in Lyons+ 1971. Kennel and Engelmann (1966) assume that only a single frequency can be associated with each wave vector: not necessarily true for EMIC, e.g. Lyons (1974a, 1974b) incorrectly used the Jacobian to relate the power spectral density in (ω,χ) space to that into (κ ⊥ , κ ∥ space. The correct use of the Jacobian: (1) Eliminates undesirable properties associated with N(ω) : lack of integrability, lack of superposition; and (2) Can produce orders of magnitude changes to the diffusion coefficients, but depends on the wave distribution: bigger effect for more oblique waves, and depends on the plasma parameter: bigger effect for smaller $ω_{pe}/ω_{ce}$.
Magnetic reconnection is the underlying mechanism in solar flares. Magnetic reconnection is an astrophysical process in an electrically conducting plasma where neighboring magnetic field lines running anti-parallel break and reconnection therefore exchanging the direction of their paths. The result of this process is the magnetic field energy converting to kinetic and thermal energy which is explosively released. The scale of a solar is extremely large compared to Earth so kinetic simulations are unable to portray an accurate model. In this project, we are using an astrophysical magnetohydrodynamic (MHD) simulation code known as Athena++ with the reconnection problem generator file created by Li et al. 2018. To further study this simulation, we began testing a heating/cooling term. The results of the original file will be compared with the modified file with an implemented heating/cooling term to better understand how solar flares function.