Model for Cumulative Solar Heavy Ion Energy and Linear Energy Transfer Spectra

Xapsos, M.A.; Stauffer, C.; Jordan, Thomas; Barth, J.L.; Mewaldt, R. A.

doi:10.1109/tns.2007.910850

Cited by 69 publications

(47 citation statements)

References 15 publications

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“…Xapsos et al (2004) developed the model further into the Prediction of Solar particle Yields for Characterization of Integrated Circuits (PSYCHIC) model, which predicts proton spectra up to >327 MeV and considers solar minimum and maximum periods. The PSYCHIC model was extended to also predict cumulative solar heavy ion fluences (Xapsos et al, 2007). In addition, a model for solar electrons has been developed based on the approach of the ESP model (Taylor et al, 2011).…”

Section: Previous Models Of Sepsmentioning

confidence: 99%

Two solar proton fluence models based on ground level enhancement observations

Raukunen

Vainio

Tylka

et al. 2018

J. Space Weather Space Clim.

158

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-Solar energetic particles (SEPs) constitute an important component of the radiation environment in interplanetary space. Accurate modeling of SEP events is crucial for the mitigation of radiation hazards in spacecraft design. In this study we present two new statistical models of high energy solar proton fluences based on ground level enhancement (GLE) observations during solar cycles 19-24. As the basis of our modeling, we utilize a four parameter double power law function (known as the Band function) fits to integral GLE fluence spectra in rigidity. In the first model, the integral and differential fluences for protons with energies between 10 MeV and 1 GeV are calculated using the fits, and the distributions of the fluences at certain energies are modeled with an exponentially cut-off power law function. In the second model, we use a more advanced methodology: by investigating the distributions and relationships of the spectral fit parameters we find that they can be modeled as two independent and two dependent variables. Therefore, instead of modeling the fluences separately at different energies, we can model the shape of the fluence spectrum. We present examples of modeling results and show that the two methodologies agree well except for a short mission duration (1 year) at low confidence level. We also show that there is a reasonable agreement between our models and three well-known solar proton models (JPL, ESP and SEPEM), despite the differences in both the modeling methodologies and the data used to construct the models.

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Section: Previous Models Of Sepsmentioning

confidence: 99%

Two solar proton fluence models based on ground level enhancement observations

Raukunen

Vainio

Tylka

et al. 2018

J. Space Weather Space Clim.

158

View full text Add to dashboard Cite

show abstract

“…High-energy SEPs from large gradual events are of more than academic interest to space travel since they can constitute a significant radiation hazard for astronauts and equipment, especially beyond the Earth's magnetic field (see reviews Barth, Dyer, and Stassinopoulos 2003;Xapsos et al 2007;Cucinottta et al 2010). Furthermore, fragmentation induced by high-energy protons in the upper atmosphere can produce penetrating radiation, especially neutrons, which threaten the passengers and crew of high-altitude aircraft on trans-polar routes.…”

Section: Radiation Hazardmentioning

confidence: 99%

The Two Sources of Solar Energetic Particles

2013

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Abstract. Evidence for two different physical mechanisms for acceleration of solar energetic particles (SEPs) arose 50 years ago with radio observations of type III bursts, produced by outward streaming electrons, and type II bursts from coronal and interplanetary shock waves. Since that time we have found that the former are related to "impulsive" SEP events from impulsive flares or jets. Here, resonant stochastic acceleration, related to magnetic reconnection involving open field lines, produces not only electrons but 1000-fold enhancements of 3 He/ 4 He and of (Z>50)/O. Alternatively, in "gradual" SEP events, shock waves, driven out from the Sun by coronal mass ejections (CMEs), more democratically sample ion abundances that are even used to measure the coronal abundances of the elements. Gradual events produce by far the highest SEP intensities near Earth. Sometimes residual impulsive suprathermal ions contribute to the seed population for shock acceleration, complicating the abundance picture, but this process has now been modeled theoretically. Initially, impulsive events define a point source on the Sun, selectively filling few magnetic flux tubes, while gradual events show extensive acceleration that can fill half of the inner heliosphere, beginning when the shock reaches ~2 solar radii. Shock acceleration occurs as ions are scattered back and forth across the shock by resonant Alfvén waves amplified by the accelerated protons themselves as they stream away. These waves also can produce a streaming-limited maximum SEP intensity and plateau region upstream of the shock. Behind the shock lies the large expanse of the "reservoir", a spatially extensive trapped volume of uniform SEP intensities with invariant energy-spectral shapes where overall intensities decrease with time as the enclosing "magnetic bottle" expands adiabatically. These reservoirs now explain the slow intensity decrease that defines gradual events and was once erroneously attributed solely to slow outward diffusion of the particles. At times the reservoir from one event can contribute its abundances and even its spectra as a seed population for acceleration by a second CME-driven shock wave. Confinement of particles to magnetic flux tubes that thread their source early in events is balanced at late times by slow velocity-dependent migration through a tangled network produced by field-line random walk that is probed by SEPs from both impulsive and gradual events and even by anomalous cosmic rays from the outer heliosphere. As a practical consequence, high-energy protons from gradual SEP events can be a significant radiation hazard to astronauts and equipment in space and to the passengers of high-altitude aircraft flying polar routes.

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“…Direct measurements are from the EXPOSE-E & EXPOSE-R radiometerdosimeter on the exterior of the ISS (Dachev et al 2015(Dachev et al , 2012, the Radiation Assessment Detector on the Mars Science Lander (Zeitlin et al 2013), the Lunar Reconnaissance Orbiter (Mazur et al 2011), and the Advanced Composition Explorer probe located at lunar Lagrange point L1 (Stone et al 1998). Model results are from CREME 96 for GCRs (Tylka et al 1997), ESP-PSYCHIC for SEPs (Xapsos et al 2007(Xapsos et al , 1998, AE9/AP9 for trapped radiation in Earth orbit (Ginet et al 2013), and SHIELDOSE-2Q for dose vs. shielding thickness (Seltzer 1994;Truscott 2010). Note that AE9/AP9 is an accumulation of 32 empirical data sets spanning a 35-year period for altitudes and inclinations covering the supermajority of possible Earth orbits (Ginet et al 2013), and is currently the most accurate general tool for predicting threshold dose attributable to Earth's trapped particle radiation.…”

Section: Radiation Other Than Photonsmentioning

confidence: 99%

Space as a Tool for Astrobiology: Review and Recommendations for Experimentations in Earth Orbit and Beyond

et al. 2017

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The space environment is regularly used for experiments addressing astrobiology research goals. The specific conditions prevailing in Earth orbit and beyond, notably the radiative environment (photons and energetic particles) and the possibility to conduct long-duration measurements, have been the main motivations for developing experimental concepts to expose chemical or biological samples to outer space, or to use the reentry of a spacecraft on Earth to simulate the fall of a meteorite. This paper represents an overview of past and current research in astrobiology conducted in Earth orbit and beyond, with a special focus on ESA missions such as Biopan, STONE (on Russian FOTON capsules) and EXPOSE facilities (outside the International Space Station). The future of exposure platforms is discussed, notably how they can be improved for better science return, and how to incorporate the use of small satellites such as those built in cubesat format.

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Model for Cumulative Solar Heavy Ion Energy and Linear Energy Transfer Spectra

Cited by 69 publications

References 15 publications

Two solar proton fluence models based on ground level enhancement observations

Two solar proton fluence models based on ground level enhancement observations

The Two Sources of Solar Energetic Particles

Space as a Tool for Astrobiology: Review and Recommendations for Experimentations in Earth Orbit and Beyond

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