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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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NASA NTRS1992

The Solar Wind Ion Composition Spectrometer

The Solar Wind Ion Composition Spectrometer (SWICS) on Ulysses is designed to determine uniquely the elemental and ionic-charge composition, and the temperatures and mean speeds of all major solar-wind ions, from H through Fe, at solar wind speeds ranging from 175 km/s (protons) to 1280 km/s (Fe(8+)). The instrument, which covers an energy per charge range from 0.16 to 59.6 keV/e in about 13 min, combines an electrostatic analyzer with postacceleration, followed by a time-of-flight and energy measurement. The measurements made by SWICS will have an impact on many areas of solar and heliospheric physics, in particular providing essential and unique information on: (1) conditions and processes in the region of the corona where the solar wind is accelerated; (2) the location of the source regions of the solar wind in the corona; (3) coronal heating processes; (4) the extent and causes of variations in the composition of the solar atmosphere; (5) plasma processes in the solar wind; (6) the acceleration of energetic particles in the solar wind; (7) the thermalization and acceleration of interstellar ions in the solar wind, and their composition; and (8) the composition, charge states, and behavior of the plasma in various regions of the Jovian magnetosphere.

Gloeckler, G.↗
NASA NTRS1995

Initiation-promotion model of tumor prevalence in mice from space radiation exposures

Exposures in space consist of low-level background components from galactic cosmic rays (GCR), occasional intense-energetic solar-particle events, periodic passes through geomagnetic-trapped radiation, and exposure from possible onboard nuclear-propulsion engines. Risk models for astronaut exposure from such diverse components and modalities must be developed to assure adequate protection in future NASA missions. The low-level background exposures (GCR), including relativistic heavy ions (HZE), will be the ultimate limiting factor for astronaut career exposure. We consider herein a two-mutation, initiation-promotion, radiation-carcinogenesis model in mice in which the initiation stage is represented by a linear kinetics model of cellular repair/misrepair, including the track-structure model for heavy ion action cross-sections. The model is validated by comparison with the harderian gland tumor experiments of Alpen et al. for various ion beams. We apply the initiation-promotion model to exposures from galactic cosmic rays, using models of the cosmic-ray environment and heavy ion transport, and consider the effects of the age of the mice prior to and after the exposure and of the length of time in space on predictions of relative risk. Our results indicate that biophysical models of age-dependent radiation hazard will provide a better understanding of GCR risk than models that rely strictly on estimates of the initial slopes of these radiations.

NASA Discipline Radiation Health↗
NASA NTRS2011

Science of Opportunity: Heliophysics on the FASTSAT Mission and STP-S26

The FASTSAT spacecraft, which was launched on November 19, 2010 on the DoD STP-S26 mission, carries three instruments developed in joint collaboration by NASA GSFC and the US Naval Academy: PISA, TTl, and MINI_ME.I,1 As part of a rapid-development, low-cost instrument design and fabrication program, these instruments were a perfect match for FASTSAT, which was designed and built in less than one year. These instruments, while independently developed, provide a collaborative view of important processes in the upper atmosphere relating to solar and energetic particle input, atmospheric response, and ion outflow. PISA measures in-situ irregularities in electron number density, TIl provides limb measurements of the atomic oxygen temperature profile with altitude, and MINI-ME provides a unique look at ion populations by a remote sen sing technique involving neutral atom imaging. Together with other instruments and payloads on STP-S26 such as the NSF RAX mission, FalconSat-5, and NanoSail-D (launched as a tertiary payload from FASTSAT), these instruments provide a valuable "constellation of opportunity" for following the now of energy and charged and neutral particles through the upper atmosphere. Together, and for a small fraction of the price of a major mission, these spacecraft will measure the energetic electrons impacting the upper atmosphere, the ions leaving it, and the large-scale plasma and neutral response to these energy inputs. The result will be a new model for maximizing scientific return from multiple small, distributed payloads as secondary payloads on a larger launch vehicle.

Rowland, Douglas E.↗
NASA NTRS2012

Workshop Report on Space Weather Risks and Society

As technological innovations produce new capabilities, complexities, and interdependencies, our susceptibility to the societal impacts of space weather increase. There is real concern in the scientific community that our infrastructure would be at significant risk if a major geomagnetic storm should occur. To discuss the societal impacts of space weather, we brought together an interdisciplinary group of subject matter experts and societal stakeholders to participate in a workshop entitled Space Weather Risks and Society. The workshop was held at Ames Research Center (ARC) on 15-16 October 2011. The workshop was co-sponsored by NASA Ames Research Center (ARC), the Lockheed Martin Advanced Technology Center (LMATC), the Space Weather Prediction Center (SWPC, part of the National Oceanic and Atmospheric Administration NOAA), and the Rutherford Appleton Laboratory (RAL, part of the UK Science and Technology Facilities Council STFC). The workshop is part of a series of informal weekend workshops hosted by Center Director Pete Worden.

coronal mass ejections↗
NASA NTRS2009

Relation Between Type II Bursts and CMEs Inferred from STEREO Observations

The inner coronagraph (COR1) of the Solar Terrestrial Relations Observatory (STEREO) mission has made it possible to observe CMEs in the spatial domain overlapping with that of the metric type II radio bursts. The type II bursts were associated with generally weak flares (mostly B and C class soft X-ray flares), but the CMEs were quite energetic. Using CME data for a set of type II bursts during the declining phase of solar cycle 23, we determine the CME height when the type II bursts start, thus giving an estimate of the heliocentric distance at which CME-driven shocks form. This distance has been determined to be approx. 1.5Rs (solar radii), which coincides with the distance at which the Alfven speed profile has a minimum value.We also use type II radio observations from STEREO/WAVES and Wind/WAVES observations to show that CMEs with moderate speed drive either weak shocks or no shock at all when they attain a height where the Alfven speed peaks (approx. 3Rs - 4Rs). Thus the shocks seem to be most efficient in accelerating electrons in the heliocentric distance range of 1.5Rs to 4Rs. By combining the radial variation of the CME speed in the inner corona (CME speed increase) and interplanetary medium (speed decrease) we were able to correctly account for the deviations from the universal drift-rate spectrum of type II bursts, thus confirming the close physical connection between type II bursts and CMEs. The average height (approx 1.5Rs) of STEREO CMEs at the time of type II bursts is smaller than that (2.2Rs) obtained for SOHO (Solar and Heliospheric Observatory) CMEs. We suggest that this may indicate, at least partly, the density reduction in the corona between the maximum and declining phases, so a given plasma level occurs closer to the Sun in the latter phase. In two cases, there was a diffuse shock-like feature ahead of the main body of the CME, indicating a standoff distance of 1Rs - 2Rs by the time the CME left the LASCO field of view.

Solar Energetic Particles↗
NASA NTRS2012

Comparison of Dst Forecast Models for Intense Geomagnetic Storms

We have compared six disturbance storm time (Dst) forecast models using 63 intense geomagnetic storms (Dst <=100 nT) that occurred from 1998 to 2006. For comparison, we estimated linear correlation coefficients and RMS errors between the observed Dst data and the predicted Dst during the geomagnetic storm period as well as the difference of the value of minimum Dst (Delta Dst(sub min)) and the difference in the absolute value of Dst minimum time (Delta t(sub Dst)) between the observed and the predicted. As a result, we found that the model by Temerin and Li gives the best prediction for all parameters when all 63 events are considered. The model gives the average values: the linear correlation coefficient of 0.94, the RMS error of 14.8 nT, the Delta Dst(sub min) of 7.7 nT, and the absolute value of Delta t(sub Dst) of 1.5 hour. For further comparison, we classified the storm events into two groups according to the magnitude of Dst. We found that the model of Temerin and Lee is better than the other models for the events having 100 <= Dst < 200 nT, and three recent models (the model of Wang et al., the model of Temerin and Li, and the model of Boynton et al.) are better than the other three models for the events having Dst <= 200 nT.

Geomagnetic Storms↗
NASA NTRS2023

The Living With a Star Space Environment Testbed Payload

The objectives, instrumentation, methods and data leading up to launch of the NASA Living With a Star (LWS) Space Environment Testbed (SET) payload onboard the Air Force Research Laboratory Demonstration and Science Experiments (DSX) spacecraft are described. The experiments characterize the space radiation environment and how it affects hardware performance. The payload consists of a compact space weather instrument and a carrier containing four board experiments.

Demonstration and Science Experiments (DSX)↗
NASA NTRS1975

Anisotropy measurements of nearly 50 KeV solar protons

The Energetic Particles Experiment on IMP-7 measures the angular distribution of 50-200 keV solar protons in 16 sectors. The velocity of 50 keV protons may be less than 5 times that of the solar wind. A generalized nonlinear Compton-Getting point transformation into the co-moving frame that contains no assumptions as to the angular distribution of either the spectrum or intensity is presented. Nearly 50 keV proton data in the spacecraft frame exhibit an anisotropy ratio that is large (not less than 5) and radial throughout the October 29, 1972 event lasting more than 9 days at this energy. This anisotropy argues against impulsive injection and diffusive decay in the inner solar system. Application of the transformation to the data reveals a long lasting residual anisotropy in the co-moving frame with protons streaming from the sun. Differences between the co-moving frame and solar wind frame velocities suggest residual electric fields upstream from the bow shock.

Gold, R. E.↗
NASA NTRS1972

Association between interplanetary shock waves and delayed solar particle events.

In studying the propagation of energetic charged particles from a large solar flare, we can no longer regard the interplanetary medium as remaining in a steady state; disturbances in the flow of solar wind from these flares may have great effects on the observed fluxes of charged particles. Delayed particle events, also known as 'energetic storm particle' events, may exhibit an increase by an order of magnitude or greater in the flux of protons above 10 MeV over a period of the order of 6 hours. These events are seen in association with the passage of an interplanetary shock past the earth. It is proposed that the particles are accelerated locally at the time of the passage of the interplanetary blast wave.

Datlowe, D.↗
NASA NTRS1980

Thermal iron ions in high speed solar wind streams Detection by the IMP 7/8 energetic particle experiments

The first measurements of the abundance of iron ions in high speed (greater than 600 km/s) solar wind streams have been made with the NOAA/JHU energetic particles experiments (EPE) on IMP 7/8. The identification of iron ions is quantitatively established using 4 years of observations and heavy ion accelerator calibrations of detectors similar to those flown on the spacecraft. Preliminary estimates of the Fe/H ratio are within a factor of 2 of the adopted coronal abundance (0.00005), and there is some evidence that Fe/H may remain approximately constant within a given stream. In the peaks of fast streams (700-800 km/s), about 50 iron ion counts are obtained every 20 s, offering the possibility of studying the Fe/H ratio with approximately 1 m time resolution in high speed streams throughout the decline of Solar Cycle 20 and the rise of Solar Cycle 21.

Mitchell, D. G.↗
NASA NTRS1978

The radial variation of corotating energetic particle streams in the inner and outer solar system

Spacecraft observations of 0.9 to 2.2 MeV protons are used to evaluate the radial gradient of long-lived corotating energetic particle streams for several time periods from mid-1973 to mid-1976. New evidence is presented for a positive gradient between 0.3 and some 3-4 AU and a negative one beyond some 3-5 AU. The relation between the corotating events in the inner solar system and the accompanying interplanetary magnetic field and solar wind is examined. It is shown, independently of possible secondary latitudinal effects, that between 0.3 and 1 AU, in a region where gradients up to 300%/AU exist, the particle stream is propagating inside a fast solar wind stream in a region adjacent to low- and high-speed stream interactions.

Van Hollebeke, M. A. I.↗