Search Results - "Spence, E"

A simple proof that the hp-FEM does not suffer from the pollution effect for the constant-coefficient full-space Helmholtz equation by Spence, E. A.

“…In d dimensions, accurately approximating an arbitrary function oscillating with frequency ≲ k requires ∼ k d degrees of freedom. A numerical method for…”
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A sharp relative-error bound for the Helmholtz h-FEM at high frequency by Lafontaine, D., Spence, E. A., Wunsch, J.

“…For the h -finite-element method ( h -FEM) applied to the Helmholtz equation, the question of how quickly the meshwidth h must decrease with the frequency k to…”
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Effect of EMIC waves on relativistic and ultrarelativistic electron populations: Ground-based and Van Allen Probes observations by Usanova, M. E., Drozdov, A., Orlova, K., Mann, I. R., Shprits, Y., Robertson, M. T., Turner, D. L., Milling, D. K., Kale, A., Baker, D. N., Thaller, S. A., Reeves, G. D., Spence, H. E., Kletzing, C., Wygant, J.

“…We study the effect of electromagnetic ion cyclotron (EMIC) waves on the loss and pitch angle scattering of relativistic and ultrarelativistic electrons during…”
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Electron Acceleration in the Heart of the Van Allen Radiation Belts by Reeves, G. D., Spence, H. E., Henderson, M. G., Morley, S. K., Friedel, R. H. W., Funsten, H. O., Baker, D. N., Kanekal, S. G., Blake, J. B., Fennell, J. F., Claudepierre, S. G., Thorne, R. M., Turner, D. L., Kletzing, C. A., Kurth, W. S., Larsen, B. A., Niehof, J. T.

“…The Van Allen radiation belts contain ultrarelativistic electrons trapped in Earth's magnetic field. Since their discovery in 1958, a fundamental unanswered…”
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Shock‐induced prompt relativistic electron acceleration in the inner magnetosphere by Foster, J. C., Wygant, J. R., Hudson, M. K., Boyd, A. J., Baker, D. N., Erickson, P. J., Spence, H. E.

“…We present twin Van Allen Probes spacecraft observations of the effects of a solar wind shock impacting the magnetosphere on 8 October 2013. The event provides…”
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Coercive second-kind boundary integral equations for the Laplace Dirichlet problem on Lipschitz domains by Chandler-Wilde, S. N., Spence, E. A.

“…We present new second-kind integral-equation formulations of the interior and exterior Dirichlet problems for Laplace’s equation. The operators in these…”
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Wave-driven butterfly distribution of Van Allen belt relativistic electrons by Xiao, Fuliang, Yang, Chang, Su, Zhenpeng, Zhou, Qinghua, He, Zhaoguo, He, Yihua, Baker, D. N., Spence, H. E., Funsten, H. O., Blake, J. B.

“…Van Allen radiation belts consist of relativistic electrons trapped by Earth's magnetic field. Trapped electrons often drift azimuthally around Earth and…”
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The Magnetic Electron Ion Spectrometer (MagEIS) Instruments Aboard the Radiation Belt Storm Probes (RBSP) Spacecraft by Blake, J. B., Carranza, P. A., Claudepierre, S. G., Clemmons, J. H., Crain, W. R., Dotan, Y., Fennell, J. F., Fuentes, F. H., Galvan, R. M., George, J. S., Henderson, M. G., Lalic, M., Lin, A. Y., Looper, M. D., Mabry, D. J., Mazur, J. E., McCarthy, B., Nguyen, C. Q., O’Brien, T. P., Perez, M. A., Redding, M. T., Roeder, J. L., Salvaggio, D. J., Sorensen, G. A., Spence, H. E., Yi, S., Zakrzewski, M. P.

“…This paper describes the Magnetic Electron Ion Spectrometer (MagEIS) instruments aboard the RBSP spacecraft from an instrumentation and engineering point of…”
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A statistical study of EMIC waves observed by Cluster: 1. Wave properties by Allen, R. C., Zhang, J.-C., Kistler, L. M., Spence, H. E., Lin, R.-L., Klecker, B., Dunlop, M. W., André, M., Jordanova, V. K.

“…Electromagnetic ion cyclotron (EMIC) waves are an important mechanism for particle energization and losses inside the magnetosphere. In order to better…”
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Rapid local acceleration of relativistic radiation-belt electrons by magnetospheric chorus by Thorne, R. M., Li, W., Ni, B., Ma, Q., Bortnik, J., Chen, L., Baker, D. N., Spence, H. E., Reeves, G. D., Henderson, M. G., Kletzing, C. A., Kurth, W. S., Hospodarsky, G. B., Blake, J. B., Fennell, J. F., Claudepierre, S. G., Kanekal, S. G.

“…High-resolution measurements of electrons obtained by satellite during the geomagnetic storm of 9 October 2012 together with a data-driven global wave model…”
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Evolution and slow decay of an unusual narrow ring of relativistic electrons near L ~ 3.2 following the September 2012 magnetic storm by Thorne, R. M., Li, W., Ni, B., Ma, Q., Bortnik, J., Baker, D. N., Spence, H. E., Reeves, G. D., Henderson, M. G., Kletzing, C. A., Kurth, W. S., Hospodarsky, G. B., Turner, D., Angelopoulos, V.

“…A quantitative analysis is performed on the decay of an unusual ring of relativistic electrons between 3 and 3.5 RE, which was observed by the Relativistic…”
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Radiation belt electron acceleration by chorus waves during the 17 March 2013 storm by Li, W., Thorne, R. M., Ma, Q., Ni, B., Bortnik, J., Baker, D. N., Spence, H. E., Reeves, G. D., Kanekal, S. G., Green, J. C., Kletzing, C. A., Kurth, W. S., Hospodarsky, G. B., Blake, J. B., Fennell, J. F., Claudepierre, S. G.

“…Local acceleration driven by whistler‐mode chorus waves is fundamentally important for accelerating seed electron populations to highly relativistic energies…”
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What Causes Radiation Belt Enhancements: A Survey of the Van Allen Probes Era by Boyd, A. J., Turner, D. L., Reeves, G. D., Spence, H. E., Baker, D. N., Blake, J. B.

“…We survey radiation belt enhancement events during the Van Allen Probes era to determine what mechanism is the dominant cause of enhancements and where it is…”
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The occurrence and wave properties of H+-, He+-, and O+-band EMIC waves observed by the Van Allen Probes by Saikin, A. A., Zhang, J.-C., Allen, R. C., Smith, C. W., Kistler, L. M., Spence, H. E., Torbert, R. B., Kletzing, C. A., Jordanova, V. K.

“…We perform a statistical study of electromagnetic ion cyclotron (EMIC) waves detected by the Van Allen Probes mission to investigate the spatial distribution…”
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The Relativistic Electron-Proton Telescope (REPT) Instrument on Board the Radiation Belt Storm Probes (RBSP) Spacecraft: Characterization of Earth’s Radiation Belt High-Energy Particle Populations by Baker, D. N., Kanekal, S. G., Hoxie, V. C., Batiste, S., Bolton, M., Li, X., Elkington, S. R., Monk, S., Reukauf, R., Steg, S., Westfall, J., Belting, C., Bolton, B., Braun, D., Cervelli, B., Hubbell, K., Kien, M., Knappmiller, S., Wade, S., Lamprecht, B., Stevens, K., Wallace, J., Yehle, A., Spence, H. E., Friedel, R.

“…Particle acceleration and loss in the million electron Volt (MeV) energy range (and above) is the least understood aspect of radiation belt science. In order…”
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The dependence on geomagnetic conditions and solar wind dynamic pressure of the spatial distributions of EMIC waves observed by the Van Allen Probes by Saikin, A. A., Zhang, J.‐C., Smith, C. W., Spence, H. E., Torbert, R. B., Kletzing, C. A.

“…A statistical examination on the spatial distributions of electromagnetic ion cyclotron (EMIC) waves observed by the Van Allen Probes against varying levels of…”
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A Long-Lived Relativistic Electron Storage Ring Embedded in Earth's Outer Van Allen Belt by Baker, D. N., Kanekal, S. G., Hoxie, V. C., Henderson, M. G., Li, X., Spence, H. E., Elkington, S. R., Friedel, R. H. W., Goldstein, J., Hudson, M. K., Reeves, G. D., Thorne, R. M., Kletzing, C. A., Claudepierre, S. G.

“…Since their discovery more than 50 years ago, Earth's Van Allen radiation belts have been considered to consist of two distinct zones of trapped, highly…”
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Wave-induced loss of ultra-relativistic electrons in the Van Allen radiation belts by Shprits, Yuri Y., Drozdov, Alexander Y., Spasojevic, Maria, Kellerman, Adam C., Usanova, Maria E., Engebretson, Mark J., Agapitov, Oleksiy V., Zhelavskaya, Irina S., Raita, Tero J., Spence, Harlan E., Baker, Daniel N., Zhu, Hui, Aseev, Nikita A.

“…The dipole configuration of the Earth’s magnetic field allows for the trapping of highly energetic particles, which form the radiation belts. Although…”
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Explaining the dynamics of the ultra-relativistic third Van Allen radiation belt by Mann, I. R., Ozeke, L. G., Murphy, K. R., Claudepierre, S. G., Turner, D. L., Baker, D. N., Rae, I. J., Kale, A., Milling, D. K., Boyd, A. J., Spence, H. E., Reeves, G. D., Singer, H. J., Dimitrakoudis, S., Daglis, I. A., Honary, F.

“…Since the discovery of the Van Allen radiation belts over 50 years ago, an explanation for their complete dynamics has remained elusive. Especially challenging…”
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Quantifying the radiation belt seed population in the 17 March 2013 electron acceleration event by Boyd, A. J., Spence, H. E., Claudepierre, S. G., Fennell, J. F., Blake, J. B., Baker, D. N., Reeves, G. D., Turner, D. L.

“…We present phase space density (PSD) observations using data from the Magnetic Electron Ion Spectrometer instrument on the Van Allen Probes for the 17 March…”
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