Open Access. Powered by Scholars. Published by Universities.®

Physics Commons

Open Access. Powered by Scholars. Published by Universities.®

University of New Hampshire

Series

2014

Discipline
Keyword
Publication

Articles 31 - 36 of 36

Full-Text Articles in Physics

Quantifying Hiss-Driven Energetic Electron Precipitation: A Detailed Conjunction Event Analysis, W. Li, B. Ni, R. M. Thorne, J. Bortnik, Y. Nishimura, J. C. Green, C A. Kletzing, W. S. Kurth, G. B. Hospodarsky, Harlan E. Spence, Geoffrey Reeves, J. B. Blake, Joseph F. Fennell, S. Claudepierre, X. Gu Feb 2014

Quantifying Hiss-Driven Energetic Electron Precipitation: A Detailed Conjunction Event Analysis, W. Li, B. Ni, R. M. Thorne, J. Bortnik, Y. Nishimura, J. C. Green, C A. Kletzing, W. S. Kurth, G. B. Hospodarsky, Harlan E. Spence, Geoffrey Reeves, J. B. Blake, Joseph F. Fennell, S. Claudepierre, X. Gu

Physics & Astronomy

Abstract

We analyze a conjunction event between the Van Allen Probes and the low-altitude Polar Orbiting Environmental Satellite (POES) to quantify hiss-driven energetic electron precipitation. A physics-based technique based on quasi-linear diffusion theory is used to estimate the ratio of precipitated and trapped electron fluxes (R), which could be measured by the two-directional POES particle detectors, using wave and plasma parameters observed by the Van Allen Probes. The remarkable agreement between modeling and observations suggests that this technique is applicable for quantifying hiss-driven electron scattering near the bounce loss cone. More importantly, R in the 100-300 keV energy channel measured …


Radiation Modeling In The Earth And Mars Atmospheres Using Lro/Crater With The Emmrem Module, Colin J. Joyce, Nathan A. Schwadron, Jody K. Wilson, Harlan E. Spence, Justin Kasper, Michael J. Golightly, J. B. Blake, Lawrence W. Townsend, Anthony Case, E. Semones, Sonya S. Smith, Cary Zeitlin Feb 2014

Radiation Modeling In The Earth And Mars Atmospheres Using Lro/Crater With The Emmrem Module, Colin J. Joyce, Nathan A. Schwadron, Jody K. Wilson, Harlan E. Spence, Justin Kasper, Michael J. Golightly, J. B. Blake, Lawrence W. Townsend, Anthony Case, E. Semones, Sonya S. Smith, Cary Zeitlin

Physics & Astronomy

Abstract

We expand upon the efforts of Joyce et al. (2013), who computed the modulation potential at the Moon using measurements from the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) instrument on the Lunar Reconnaissance Orbiter (LRO) spacecraft along with data products from the Earth-Moon-Mars Radiation Environment Module (EMMREM). Using the computed modulation potential, we calculate galactic cosmic ray (GCR) dose and dose equivalent rates in the Earth and Mars atmospheres for various altitudes over the course of the LRO mission. While we cannot validate these predictions by directly comparable measurement, we find that our results conform to …


An Empirically Observed Pitch-Angle Diffusion Eigenmode In The Earth's Electron Belt Near L* = 5.0, T. P. O'Brien, S. Claudepierre, J. B. Blake, Joseph F. Fennell, J. H. Clemmons, J. Roeder, Harlan E. Spence, Geoffrey Reeves, D. N. Baker Jan 2014

An Empirically Observed Pitch-Angle Diffusion Eigenmode In The Earth's Electron Belt Near L* = 5.0, T. P. O'Brien, S. Claudepierre, J. B. Blake, Joseph F. Fennell, J. H. Clemmons, J. Roeder, Harlan E. Spence, Geoffrey Reeves, D. N. Baker

Physics & Astronomy

Abstract

Using data from NASA's Van Allen Probes, we have identified a synchronized exponential decay of electron flux in the outer zone, near L* = 5.0. Exponential decays strongly indicate the presence of a pure eigenmode of a diffusion operator acting in the synchronized dimension(s). The decay has a time scale of about 4 days with no dependence on pitch angle. While flux at nearby energies and L* is also decaying exponentially, the decay time varies in those dimensions. This suggests the primary decay mechanism is elastic pitch angle scattering, which itself depends on energy and L * …


Excitation Of Emic Waves Detected By The Van Allen Probes On 28 April 2013, J. C. Zhang, A A. Saiken, Lynn M. Kistler, Charles W. Smith, Harlan E. Spence, Christoforos Mouikis, Roy B. Torbert, Bradford Larsen, Geoffrey Reeves, R. M. Skoug, H. O. Funsten, W. S. Kurth, C A. Kletzing, R. C. Allen, V K. Jordanova Jan 2014

Excitation Of Emic Waves Detected By The Van Allen Probes On 28 April 2013, J. C. Zhang, A A. Saiken, Lynn M. Kistler, Charles W. Smith, Harlan E. Spence, Christoforos Mouikis, Roy B. Torbert, Bradford Larsen, Geoffrey Reeves, R. M. Skoug, H. O. Funsten, W. S. Kurth, C A. Kletzing, R. C. Allen, V K. Jordanova

Physics & Astronomy

Abstract

We report the wave observations, associated plasma measurements, and linear theory testing of electromagnetic ion cyclotron (EMIC) wave events observed by the Van Allen Probes on 28 April 2013. The wave events are detected in their generation regions as three individual events in two consecutive orbits of Van Allen Probe-A, while the other spacecraft, B, does not detect any significant EMIC wave activity during this period. Three overlapping H+ populations are observed around the plasmapause when the waves are excited. The difference between the observational EMIC wave growth parameter (Eh) and the theoretical EMIC instability parameter …


Prompt Energization Of Relativistic And Highly Relativistic Electrons During A Substorm Interval: Van Allen Probes Observations, J. C. Foster, P. J. Erickson, D. N. Baker, S. Claudepierre, C A. Kletzing, W. S. Kurth, Geoffrey Reeves, S. A. Thaller, Harlan E. Spence, Y. Y. Shprits, J. R. Wygant Jan 2014

Prompt Energization Of Relativistic And Highly Relativistic Electrons During A Substorm Interval: Van Allen Probes Observations, J. C. Foster, P. J. Erickson, D. N. Baker, S. Claudepierre, C A. Kletzing, W. S. Kurth, Geoffrey Reeves, S. A. Thaller, Harlan E. Spence, Y. Y. Shprits, J. R. Wygant

Physics & Astronomy

Abstract

On 17 March 2013, a large magnetic storm significantly depleted the multi-MeV radiation belt. We present multi-instrument observations from the Van Allen Probes spacecraft Radiation Belt Storm Probe A and Radiation Belt Storm Probe B at ~6 Re in the midnight sector magnetosphere and from ground-based ionospheric sensors during a substorm dipolarization followed by rapid reenergization of multi-MeV electrons. A 50% increase in magnetic field magnitude occurred simultaneously with dramatic increases in 100 keV electron fluxes and a 100 times increase in VLF wave intensity. The 100 keV electrons and intense VLF waves provide a seed population and energy …


Nonstorm Time Dynamics Of Electron Radiation Belts Observed By The Van Allen Probes, Zhenpeng Su, Fuliang Xiao, Huinan Zheng, Zhaoguo He, Hui Zhu, Min Zhang, Chao Shen, Yuming Wang, Shui Wang, C A. Kletzing, W. S. Kurth, G. B. Hospodarsky, Harlan E. Spence, Geoffrey Reeves, H. O. Funsten, J. B. Blake, D. N. Baker Jan 2014

Nonstorm Time Dynamics Of Electron Radiation Belts Observed By The Van Allen Probes, Zhenpeng Su, Fuliang Xiao, Huinan Zheng, Zhaoguo He, Hui Zhu, Min Zhang, Chao Shen, Yuming Wang, Shui Wang, C A. Kletzing, W. S. Kurth, G. B. Hospodarsky, Harlan E. Spence, Geoffrey Reeves, H. O. Funsten, J. B. Blake, D. N. Baker

Physics & Astronomy

Abstract

Storm time electron radiation belt dynamics have been widely investigated for many years. Here we present a rarely reported nonstorm time event of electron radiation belt evolution observed by the Van Allen Probes during 21-24 February 2013. Within 2 days, a new belt centering around L=5.8 formed and gradually merged with the original outer belt, with the enhancement of relativistic electron fluxes by a factor of up to 50. Strong chorus waves (with power spectral density up to 10-4nT2/Hz) occurred in the region L>5. Taking into account the local acceleration driven by these chorus …