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Your search keyword '"Mazur, J."' showing total 19 results
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19 results on '"Mazur, J."'

1. SAMPEX Observations of the South Atlantic Anomaly Secular Drift During Solar Cycles 22-24

Author

Jones, A. D, Kanekal, S. G, Baker, D. N, Klecker, B, Looper, M.D, Mazur, J. E, and Schiller, Q

Subjects
Geophysics
Abstract

It is observed that charged particle intensities are very high near the South Atlantic anomaly (SAA) and are a potential hazard to spacecraft passing through the region. In this study, we examine the secular drift of the SAA location at approximately 400-600 kilometers altitude over nearly two solar cycles, using particle count rates to trace the geomagnetic field lines in the region near the SAA. We use data from the Low-Energy Ion Composition Analyzer sensor on board the SAMPEX (Solar, Anomalous, and Magnetospheric Particle Explorer) spacecraft to measure both the longitudinal and latitudinal drifts of the SAA. We find that the longitudinal drift rate is 0.20 plus or minus 0.04 degrees west per year and that the latitudinal drift rate is 0.11 plus or minus 0.01 degrees south per year. These measurements are compared with the IGRF12 (International Geomagnetic Reference Field) model calculations based on an analysis of magnetic field minima in the region of the SAA. Our results, which are in good agreement with model results and prior measurements when declining spacecraft altitude is taken into account, have important space weather implications.

Published
2017
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3. Solar modulation of the deep space galactic cosmic ray lineal energy spectrum measured by CRaTER, 2009-2014

Author

W., Case A., A., Schwadron N., E., Spence H., E., Mazur J., J., Joyce C., D., Looper M., Jordan, A., R., Rios R., W., Townsend L., C., Kasper J., B., Blake J., Smith, S., and Wilson, J.

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Physics::Space Physics, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics
Abstract

The Cosmic Ray Telescope for the Effects of Radiation (CRaTER) is an energetic particle detector flying aboard the Lunar Reconnaissance Orbiter. Since arriving at the Moon in 2009, CRaTER has observed the deep solar minimum of solar cycle 23, the ascending phase of cycle 24, the very weak maximum of cycle 24, and in recent months, what appears to be the start of the descending phase of cycle 24. In earlier work, we presented lineal energy spectra of galactic cosmic rays (GCRs) at solar minimum for different shielding depths. The long period of CRaTER observations allows us to study the evolution of these spectra as a function of solar modulation. As solar modulation increases, the total flux of GCRs decreases, and lower-energy ions are preferentially removed from the spectrum of ions that arrive in the inner heliosphere. These effects lead to modest variations in the lineal energy spectrum as a function of time. GCR fluxes at the 2009/2010 solar minimum were high by historical standards and at solar maximum remained high compared to earlier maxima.

Published
2016

5. In Situ Data and Effect Correlation During September 2017 Solar Particle Event

Author

Jiggens, P., primary, Clavie, C., additional, Evans, H., additional, O'Brien, T. P., additional, Witasse, O., additional, Mishev, A. L., additional, Nieminen, P., additional, Daly, E., additional, Kalegaev, V., additional, Vlasova, N., additional, Borisov, S., additional, Benck, S., additional, Poivey, C., additional, Cyamukungu, M., additional, Mazur, J., additional, Heynderickx, D., additional, Sandberg, I., additional, Berger, T., additional, Usoskin, I. G., additional, Paassilta, M., additional, Vainio, R., additional, Straube, U., additional, Müller, D., additional, Sánchez‐Cano, B., additional, Hassler, D., additional, Praks, J., additional, Niemelä, P., additional, Leppinen, H., additional, Punkkinen, A., additional, Aminalragia‐Giamini, S., additional, and Nagatsuma, T., additional

Published
2019
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7. Update on the Worsening Particle Radiation Environment Observed by CRaTER and Implications for Future Human Deep‐Space Exploration

Author

Schwadron, N. A., primary, Rahmanifard, F., additional, Wilson, J., additional, Jordan, A. P., additional, Spence, H. E., additional, Joyce, C. J., additional, Blake, J. B., additional, Case, A. W., additional, de Wet, W., additional, Farrell, W. M., additional, Kasper, J. C., additional, Looper, M. D., additional, Lugaz, N., additional, Mays, L., additional, Mazur, J. E., additional, Niehof, J., additional, Petro, N., additional, Smith, C. W., additional, Townsend, L. W., additional, Winslow, R., additional, and Zeitlin, C., additional

Published
2018
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8. The Deep-space Galactic Cosmic Ray Lineal Energy Spectrum at Solar Minimum

Author

W., Case A., C., Kasper J., E., Spence H., J., Zeitlin C., D., Looper M., J., Golightly M., A., Schwadron N., W., Townsend L., E., Mazur J., and B., Blake J.

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Physics::Space Physics, Astrophysics::Instrumentation and Methods for Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Physics::Geophysics
Abstract

The Cosmic Ray Telescope for the Effects of Radiation (CRaTER) instrument is an energetic particle telescope on board the Lunar Reconnaissance Orbiter spacecraft. CRaTER measures energetic charged particles that have sufficient energy to penetrate the outer shielding of the instrument (about 12 MeV/nucleon). Galactic cosmic rays (GCR) with these energies are the primary radiation concern for spacecraft and astronauts outside of the Earth's magnetosphere during times of minimal solar activity. These particles can easily penetrate typical shielding and damage electronics, causing increased electronics failure rates and single event upsets. When this radiation impacts biological cells, it causes an increased risk of cancer. The CRaTER instrument was built to characterize the radiation dose and lineal energy with unprecedented time and energy resolution and was fortuitously flown during a period of time that coincided with the highest GCR fluxes in the modern space age. We report here this worst‐case GCR lineal energy spectrum. Observations are made behind a thin aluminum window and different thicknesses of tissue‐equivalent plastic. These measurements provide important observational data points to compare with current model predictions of the dose deposited by energetic particles within a tissue‐like material.

Published
2013

9. Measurements of galactic cosmic ray shielding with the CRaTER instrument

Author

Zeitlin, C., W., Case A., E., Spence H., A., Schwadron N., Golightly, M., K., Wilson J., C., Kasper J., B., Blake J., D., Looper M., E., Mazur J., and W., Townsend L.

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Physics::Space Physics, Astrophysics::Instrumentation and Methods for Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Physics::Geophysics
Abstract

The Cosmic Ray Telescope for the Effects of Radiation (CRaTER) instrument aboard the Lunar Reconnaissance Orbiter has been measuring energetic charged particles from the galactic cosmic rays (GCRs) and solar particle events in lunar orbit since 2009. CRaTER includes three pairs of silicon detectors, separated by pieces of tissue‐equivalent plastic that shield two of the three pairs from particles incident at the zenith‐facing end of the telescope. Heavy‐ion beams studied in previous ground‐based work have been shown to be reasonable proxies for the GCRs when their energies are sufficiently high. That work, which included GCR simulations, led to predictions for the amount of dose reduction that would be observed by CRaTER. Those predictions are compared to flight data obtained by CRaTER in 2010–2011.

Published
2013

10. Solar modulation of the deep space galactic cosmic ray lineal energy spectrum measured by CRaTER, 2009–2014

Author

Zeitlin, C., primary, Case, A. W., additional, Schwadron, N. A., additional, Spence, H. E., additional, Mazur, J. E., additional, Joyce, C. J., additional, Looper, M. D., additional, Jordan, A., additional, Rios, R. R., additional, Townsend, L. W., additional, Kasper, J. C., additional, Blake, J. B., additional, Smith, S., additional, Wilson, J., additional, and Iwata, Y., additional

Published
2016
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13. Does the worsening galactic cosmic radiation environment observed by CRaTER preclude future manned deep space exploration?

Author

Schwadron, N. A., primary, Blake, J. B., additional, Case, A. W., additional, Joyce, C. J., additional, Kasper, J., additional, Mazur, J., additional, Petro, N., additional, Quinn, M., additional, Porter, J. A., additional, Smith, C. W., additional, Smith, S., additional, Spence, H. E., additional, Townsend, L. W., additional, Turner, R., additional, Wilson, J. K., additional, and Zeitlin, C., additional

Published
2014
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