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Full-Text Articles in Physics
Cusp Energetic Ions: A Bow Shock Source, S. W. Chang, J. D. Scudder, S. A. Fuselier, J. F. Fennell, K. J. Trattner, J. S. Pickett, Harlan E. Spence, J. D. Menietti, W. K. Peterson, R. P. Lepping, R. Friedel
Cusp Energetic Ions: A Bow Shock Source, S. W. Chang, J. D. Scudder, S. A. Fuselier, J. F. Fennell, K. J. Trattner, J. S. Pickett, Harlan E. Spence, J. D. Menietti, W. K. Peterson, R. P. Lepping, R. Friedel
Physics & Astronomy
Recent interpretations of cusp energetic ions observed by the POLAR spacecraft have suggested a new energization process in the cusp [Chen et al., 1997; 1998]. Simultaneous enhancement of H+, He+2, and O>+2 fluxes indicates that they are of solar wind origin. In the present study, we examine H+ and He+2 energy spectra from 20 eV to several 100 keV measured by the Hydra, Toroidal Imaging Mass-Angle Spectrograph (TIMAS), and Charge and Mass Magnetospheric Ion Composition Experiment (CAMMICE) on POLAR. The combined spectrum for each species is shown to be continuous with a …
The Global Response Of Relativistic Radiation Belt Electrons To The January 1997 Magnetic Cloud, G. D. Reeves, D. N. Baker, R. D. Belian, J. B. Blake, T. E. Cayton, J. F. Fennell, R. H.W. Friedel, M. M. Meier, R. S. Selesnick, Harlan E. Spence
The Global Response Of Relativistic Radiation Belt Electrons To The January 1997 Magnetic Cloud, G. D. Reeves, D. N. Baker, R. D. Belian, J. B. Blake, T. E. Cayton, J. F. Fennell, R. H.W. Friedel, M. M. Meier, R. S. Selesnick, Harlan E. Spence
Physics & Astronomy
In January 1997 a large fleet of NASA and US military satellites provided the most complete observations to date of the changes in >2 MeV electrons during a geomagnetic storm. Observations at geosynchronous orbit revealed a somewhat unusual two-peaked enhancement in relativistic electron fluxes [ Reeves et al., 1998]. In the heart of the radiation belts at L ≈ 4, however, there was a single enhancement followed by a gradual decay. Radial profiles from the POLAR and GPS satellites revealed three distinct phases. (1) In the acceleration phase electron fluxes increased simultaneously at L ≈ 4–6. (2) During the …
Coronal Mass Ejections, Magnetic Clouds, And Relativistic Magnetospheric Electron Events: Istp, D. N. Baker, T. I. Pulkkinen, X. Li, S. G. Kanekal, J. B. Blake, R. S. Selesnick, M. G. Henderson, G. D. Reeves, Harlan E. Spence, G. Rostoker
Coronal Mass Ejections, Magnetic Clouds, And Relativistic Magnetospheric Electron Events: Istp, D. N. Baker, T. I. Pulkkinen, X. Li, S. G. Kanekal, J. B. Blake, R. S. Selesnick, M. G. Henderson, G. D. Reeves, Harlan E. Spence, G. Rostoker
Physics & Astronomy
The role of high-speed solar wind streams in driving relativistic electron acceleration within the Earth's magnetosphere during solar activity minimum conditions has been well documented. The rising phase of the new solar activity cycle (cycle 23) commenced in 1996, and there have recently been a number of coronal mass ejections (CMEs) and related “magnetic clouds” at 1 AU. As these CME/cloud systems interact with the Earth's magnetosphere, some events produce substantial enhancements in the magnetospheric energetic particle population while others do not. This paper compares and contrasts relativistic electron signatures observed by the POLAR, SAMPEX, Highly Elliptical Orbit, and geostationary …
The Discovery Of Trapped Energetic Electrons In The Outer Cusp, R. B. Sheldon, Harlan E. Spence, J. D. Sullivan, T. A, Fritz, Jiasheng Chen
The Discovery Of Trapped Energetic Electrons In The Outer Cusp, R. B. Sheldon, Harlan E. Spence, J. D. Sullivan, T. A, Fritz, Jiasheng Chen
Physics & Astronomy
We report on the POLAR/CEPPAD discovery of a trapped, 60°<θ<120° pitch angle electron population in the outer cusp (7−9+ Re), whose energetic electron component extends from below 30 keV to ∼2 MeV. Because the time variability in the outer cusp precludes mapping with POLAR, we have carried out test particle simulations using the Tsyganenko 1996 model (T96) to demonstrate the trapping of these energy electrons in the outer cusp region and the resonant frequencies of its trapped motion. We discuss the boundaries and regions of the cusp trap and show that it is analogous to the dipole trap. We show that the phase space densities observed there are equal or greater than the phase space densities observed in the radiation belts at constant magnetic moment, thus allowing the possibility of diffusive filling of the radiation belts from the cusp
Ampte/Cce‐Scatha Simultaneous Observations Of Substorm‐Associated Magnetic Fluctuations, S. Ohtani, K. Takahashi, T. Higuchi, A. T. Y. Lui, Harlan E. Spence, J. F. Fennell
Ampte/Cce‐Scatha Simultaneous Observations Of Substorm‐Associated Magnetic Fluctuations, S. Ohtani, K. Takahashi, T. Higuchi, A. T. Y. Lui, Harlan E. Spence, J. F. Fennell
Physics & Astronomy
This study examines substorm-associated magnetic field fluctuations observed by the AMPTE/CCE and SCATHA satellites in the near-Earth tail. Three tail reconfiguration events are selected, one event on August 28, 1986, and two consecutive events on August 30, 1986. The fractal analysis was applied to magnetic field measurements of each satellite. The result indicates that (1) the amplitude of the fluctuation of the north-south magnetic component is larger, though not overwhelmingly, than the amplitudes of the other two components and (2) the magnetic fluctuations do have a characteristic timescale, which is several times the proton gyroperiod. In the examined events the …
Cusp Energetic Particle Events: Implications For A Major Acceleration Region Of The Magnetosphere, J. Chen, T. A. Fritz, R. B. Sheldon, Harlan E. Spence, W. N. Spjeldvik, J. F. Fennell, S. Livi, C. T. Russell, J. S. Pickett, D. A. Gurnett
Cusp Energetic Particle Events: Implications For A Major Acceleration Region Of The Magnetosphere, J. Chen, T. A. Fritz, R. B. Sheldon, Harlan E. Spence, W. N. Spjeldvik, J. F. Fennell, S. Livi, C. T. Russell, J. S. Pickett, D. A. Gurnett
Physics & Astronomy
The Charge and Mass Magnetospheric Ion Composition Experiment (CAMMICE) on board the Polar spacecraft observed 75 energetic particle events in 1996 while the satellite was at apogee. All of these events were associated with a decrease in the magnitude of the local magnetic field measured by the Magnetic Field Experiment (MFE) on Polar. These new events showed several unusual features: (1) They were detected in the dayside polar cusp near the apogee of Polar with about 79% of the total events in the afternoonside and 21% in the morningside; (2) an individual event could last for hours; (3) the measured …