Analysis of solar-cell array panel (SAP) data from the Arase satellite orbiting in the inner magnetosphere showed a clear degradation of solar cells that could be attributed to trapped protons with energies greater than 6 MeV. Proton fluence was determined based on variations in the open-circuit voltage (Voc) of the solar cells, which we compared with that expected based on various distribution models (AP8MAX, AP9 mean and CRRESPRO quiet) of trapped protons. We found a general agreement, confirming the major contribution of trapped protons to the degradation, as well as a slight difference in the fluence expected based on the model calculations. To minimize this difference, we slightly modified the models, and found that concentrating the energetic protons on the magnetic equator provided a better agreement. Our results indicate that >6 MeV protons also has the equatorial concentration as reported for >18 MeV protons from the Van Allen Probes observation, and are interpreted as two components of the trapped protons, i.e., those of solar energetic particle (SEP) origin have an anisotropic pitch-angle distribution and are confined near the magnetic equator.
References
[1]
Mauk, B.H., Fox, N.J., Kanekal, S.G., Kessel, R.L., Sibeck, D.G. and Ukhorskiy, A. (2013) Science Objectives and Rationale for the Radiation Belt Storm Probes Mission. Space Science Reviews, 179, 3-27. https://doi.org/10.1007/s11214-012-9908-y
[2]
Selesnick, R.S., Baker, D.N., Jaynes, A.N., Li, X., Kanekal, S.G., Hudson, M.K. and Kress, B.T. (2014) Observations of the Inner Radiation Belt: CRAND and Trapped Solar Protons. Journal of Geophysical Research, 119, 6541-6552. https://doi.org/10.1002/2014JA020188
[3]
Fennel, J.F., Blake, J.B., Claudepierre, S., Mazur, J., Kanekal, S., O’Brien, P., Baker, D., Crain, W., Mabry, D. and Clemmons, J. (2016) Current Energetic Particle Sensors. Journal of Geophysical Research: Space Physics, 121, 8840-8858.
[4]
Ishikawa, H., Miyake, W. and Matsuoka, A. (2013) Variation of Proton Radiation Belt Deduced from Solar Cell Degradation of Akebono Satellite. Earth Planets Space, 65, 121-125. https://doi.org/10.5047/eps.2012.06.004
[5]
Miyake, W., Miyoshi, Y. and Matsuoka, A. (2014) On the Spatial Extent of the Proton Radiation Belt from Solar Cell Output Variation of the Akebono Satellite. Advances in Space Research, 53, 1603-1609. https://doi.org/10.1016/j.asr.2014.03.002
[6]
Miyake, W., Miyoshi, Y. and Matsuoka, A. (2015) An Empirical Modeling of Spatial Distribution of Trapped Protons from Solar Cell Degradation of the Akebono Satellite. Advances in Space Research, 56, 2575-2581. https://doi.org/10.1016/j.asr.2015.10.021
[7]
Miyoshi, Y., Shinohara, I., Takashima, T., Asamura, K., Higashio, N., Mitani, T., Kasahara, S., Yokota, S., Kazama, Y., Wang, S.-Y., Tam, S.W., Ho, P.T.P., Kasahara, Y., Kasaba, Y., Yagitani S., Matsuoka A., Kojima H., Katoh, H., Shiokawa, K. and Seki, K. (2018) Geospace Exploration Project ERG. Earth Planets Space, 70, 101. https://doi.org/10.1186/s40623-018-0862-0
[8]
Yokota, S., Kasahara, S., Mitani, T., Asamura, K, Hirahara, M., Takashima, T., Yamamoto, K. and Shibano, Y. (2017) Medium-Energy Particle Experiments-Ion Mass Analyzer (MEP-i) Onboard ERG (Arase). Earth Planets Space, 69, 172. https://doi.org/10.1186/s40623-017-0754-8
[9]
Knoll, G.F. (1989) Radiation Detection and Measurement. Wiley, New York.
[10]
Ginet, G.P., O’Brien, T.P., Huston, S.L., Johnston, W.R., Guild, T.B., Friedel, R., Lindstrom, C.D., Roth, C.J., Whelan, P., Quinn, R.A., Madden, D., Morley, S. and Su, Y.-J. (2013) AE9, AP9 and SPM: New Models for Specifying the Trapped Energetic Particle and Space Plasma Environment. Space Science Reviews, 179, 579-615. https://doi.org/10.1007/s11214-013-9964-y
[11]
Gussenhoven, M.S., Mullen, E.G. and Brautigam, D.H. (1996) Improved Understanding of the Earth’s Radiation Belts from the CRRES Satellite. IEEE Transactions on Nuclear Science, 43, 353-368. https://doi.org/10.1109/23.490755
[12]
Patel, M.R. (2005) Spacecraft Power Systems. Boca Raton, CRC Press.
[13]
Kazama, Y. and Goka, G. (2008) A New Modeling Method of Solar Energetic Proton Events for ISO Specification. Advances in Space Research, 42, 1293-1299. https://doi.org/10.1016/j.asr.2007.12.012
[14]
Engel, M.A., Kress, B.T., Hudson, M.K. and Selesnick, R.S. (2016) Comparison of Van Allen Probes Radiation Belt Proton Data with Test Particle Simulation for the 17 March 2015 Storm. Journal of Geophysical Research: Space Physics, 121, 11,035-11,041. https://doi.org/10.1002/2016JA023333
[15]
Lorentzen, K.R., Mazur, J.E., Looper, M.D., Fennel, J.F. and Blake, J.B. (2002) Multisatellite Observations of MeV Ion Injections during Storms. Journal of Geophysical Research, 107, 1231. https://doi.org/10.1029/2001JA000276
[16]
Selesnick, R.S., Hudson, M.K. and Kress, B.T. (2010) Injection and Loss of Inner Radiation Belt Protons during Solar Proton Events and Magnetic Storms. Journal of Geophysical Research, 115, Article ID: A08211. https://doi.org/10.1029/2010JA015247
[17]
Looper, M.D., Blake, J.B. and Mewaldt, R.A. (2005) Response of the Inner Radiation Belt to the Violent Sun-Earth Connection Events of October-November 2003. Geophysical Research Letters, 32, Article ID: L03S06. https://doi.org/10.1029/2004GL021502
[18]
Mitani, T., Takashima, T., Kasahara, S., Miyake, W. and Hirahara, M. (2018) High-Energy Electron Experiment (HEP) Aboard the ERG (Arase) Spacecraft. Earth Planet Space, 70, 77. https://doi.org/10.1186/s40623-018-0853-1
[19]
Selesnick, R.S., Baker, D.N., Kanekal, S.G., Hoxie, V.C. and Li, X. (2018) Modeling the Proton Radiation Belt with Van Allen Probes Relativistic Electron-Proton Telescope Data. Journal of Geophysical Research, 123, 685-697. https://doi.org/10.1002/2017JA024661
