The Low-Energy Telescope (LET) and SEP Central Electronics for the STEREO Mission

Mewaldt, R. A.; Cohen, C. M. S.; Cook, W. R.; Cummings, A. C.; Davis, A. J.; Geier, S.; Kecman, B.; Klemic, J.; Labrador, A. W.; Leske, R. A.; Miyasaka, Hiromasa; Nguyen, Vy N.; Ogliore, R. C.; Stone, E. C.; Radocinski, R. G.; Wiedenbeck, M. E.; Hawk, J.; Shuman, S.; Rosenvinge, T. T. von; Wortman, Kristin

doi:10.1007/s11214-007-9288-x

Cited by 116 publications

(70 citation statements)

References 61 publications

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“…Recently, Sandberg et al (2014) developed a method for cross-calibrating the medium energy GOES/EPS channels with corresponding channels of the science-level IMP-8/GME instrument. The effect of this cross-correlation was validated by Rodriguez et al (2017) using STEREO observations (Mewaldt et al, 2008;von Rosenvinge et al, 2008). Sandberg et al (2014) also noted some problems with the low energy IMP-8 data, attributed to the gradual failing of the LED instrument between 1984 and 1990.…”

Section: Summary and Discussionmentioning

confidence: 83%

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: Summary and Discussionmentioning

confidence: 83%

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

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“…8.3 are associated with SEP events observed at 1 AU from the Sun, by instruments at L1 or by the twin STEREO spacecraft, or both. Proton and/or electron enhancements are observed with SoHO/ERNE (Torsti et al 1995), STEREO/LET (Mewaldt et al 2008), STEREO/HET (von Rosenvinge et al 2008), STEREO/SEPT (Müller-Mellin et al 2008), and ACE/EPAM (Gold et al 1998) over a wide range of energy (55 keV to 4 MeV for electrons and 1.6 to 130 MeV for protons). Higher energy protons are available from SoHO/EPHIN (penetrating protons at 100-1000 MeV energies) as well as from GOES/HEPAD (only for 9 of the 25 investigated Fermi/LAT events, see Fig.…”

Section: Solar Energetic Particle Events Associated With Fermi/lat Gamentioning

confidence: 99%

X-Ray, Radio and SEP Observations of Relativistic Gamma-Ray Events

Klein¹,

Tziotziou²,

Zucca³

et al. 2017

Astrophysics and Space Science Library

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The rather frequent occurrence, and sometimes long duration, ofray events at photon energies above 100 MeV challenges our understanding of particle acceleration processes at the Sun. The emission is ascribed to pion-decay photons due to protons with energies above 300 MeV. We study the X-ray and radio emissions and the solar energetic particles (SEPs) in space for a set of 25 Fermi -ray events. They are accompanied by strong SEP events, including, in most cases where the parent activity is well-connected, protons above 300 MeV. Signatures of energetic electron acceleration in the corona accompany the impulsive and early post-impulsive -ray emission. -ray emission lasting several hours accompanies in general the decay phase of long-lasting soft X-ray bursts and decametric-tokilometric type II bursts. We discuss the impact of these results on the origin of the -ray events. IntroductionThe advent of the Fermi mission showed that the Sun is an occasional, but unexpectedly frequent, emitter of -ray photons above 100 MeV. These are understood to be produced by pion decays in nuclear interactions involving protons or He-nuclei at energies above 300 MeV/nucleon. One did not expect that the Sun was able to accelerate relativistic protons and nuclei even in seemingly modest flares. These particles are rarely detected in space (<1 event per year). Furthermore, the duration, several hours, of some -ray events is much longer than that of hard X-ray signatures of electron acceleration in the impulsive flare phase.The question of how the -ray emission is related to other signatures of particle acceleration and energy release in the corona is crucial to understanding the origin of the high-energy protons. It might also be expected that such high-energy populations interacting at the Sun are accompanied by particularly energetic solar energetic particle (SEP) events. This chapter is based on 25 events. The Fermi/LAT temporal data were made available to the HESPERIA project by G. Share prior to their publication in a comprehensive paper ). The present chapter introduces the relevant process of emission and pre-Fermi observations of piondecay -rays (Sect. 8.2), and gives an overview of the Fermi/LAT observations (Sect. 8.3). Section 8.3 was prepared by Gerald Share and Ron Murphy. Related X-ray and radio observations and associated SEP events are presented in Sects. 8.4 and 8.5, respectively. Preliminary conclusions on the interpretation of the -ray events are in Sect. 8.6. Theory and Early Observations of Gamma-Ray Emission at Photon Energies >60 MeVOn 1982 Jun 3 the gamma-ray spectrometer on the Solar Maximum Mission satellite observed emission from 0.3 to 100 MeV from a X8.0 GOES-class flare (Forrest et al. 1986). The impulsive flare lasted about 1 min and was followed by a distinct harder emission phase that peaked in about 1 min and lasted for over 15 min. The energy spectrum of this sustained emission displayed a characteristic hump at photon energies above 60 MeV (Fig. 8.1a), which appeared to be consistent with th...

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“…Interesting features were seen in the particle anisotropies at both STEREO spacecraft at various times during this event, as discussed below. The Low Energy Telescope (LET) [6] onboard each STEREO spacecraft measures the composition, spectra, and time variations of SEPs from H through Ni at energies of about 2-50 MeV/nucleon. Sectored rates in 16 longitudinal viewing directions (averaging ∼12 • wide in longitude and covering ±15-20 • of latitude about the ecliptic) are accumulated onboard for 10 different element and energy bands.…”

Section: Observationsmentioning

confidence: 99%