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Full-Text Articles in Physics
Global Energetic Neutral Atom (Ena) Measurements And Their Association With The Dst Index, A. M. Jorgensen, Harlan E. Spence, M. G. Henderson, G. D. Reeves, M. Sugiura, T. Kamei
Global Energetic Neutral Atom (Ena) Measurements And Their Association With The Dst Index, A. M. Jorgensen, Harlan E. Spence, M. G. Henderson, G. D. Reeves, M. Sugiura, T. Kamei
Physics & Astronomy
We present a new global magnetospheric index that measures the intensity of the Earth's ring current through energetic neutral atoms (ENAs). We have named it the Global Energetic Neutral Index (GENI), and it is derived from ENA measurements obtained by the Imaging Proton Spectrometer (IPS), part of the Comprehensive Energetic Particle and Pitch Angle Distribution (CEPPAD) experiment on the POLAR satellite. GENI provides a simple orbit-independent global sum of ENAs measured with IPS. Actual ENA measurements for the same magnetospheric state look different when seen from different points in the POLAR orbit. In addition, the instrument is sensitive …
Initial Polar Mfe Observation Of Substorm Signatures In The Polar Magnetosphere, H. Kawano, G. Le, C. T. Russell, G. Rostoker, T. Mukai, Harlan E. Spence
Initial Polar Mfe Observation Of Substorm Signatures In The Polar Magnetosphere, H. Kawano, G. Le, C. T. Russell, G. Rostoker, T. Mukai, Harlan E. Spence
Physics & Astronomy
This paper studies substorm influences in the polar magnetosphere using data from the POLAR magnetic field experiment (MFE). The POLAR spacecraft remains in the high altitude polar magnetosphere for extended periods around apogee. There it can stay at nearly constant altitude through all phases of a substorm, which was not possible on previous missions. We report such an event on March 28, 1996. Ground magnetometers monitored substorm activity, while the POLAR spacecraft, directly over the pole at (−0.8, −0.6, 8.5) RE in GSM coordinates, observed a corresponding perturbation in the total magnetic field strength. The total magnetic field first …
First Polar And 1995-034 Observations Of The Midaltitude Cusp During A Persistent Northward Imf Condition, M. Grande, J. Fennell, S. Livi, B. Kellett, C. Perry, P. Anderson, J. Roeder, Harlan E. Spence, T. Fritz, B. Wilken
First Polar And 1995-034 Observations Of The Midaltitude Cusp During A Persistent Northward Imf Condition, M. Grande, J. Fennell, S. Livi, B. Kellett, C. Perry, P. Anderson, J. Roeder, Harlan E. Spence, T. Fritz, B. Wilken
Physics & Astronomy
We present the first observations by Polar and 1995-034 of the mid-altitude cusp. On May 29, 1996, the Polar and 1995-034 spacecraft crossed into an extended cusp region. The region was characterized by intense fluxes of solar wind like ions in the energy range 1–10 keV that had angular distributions that showed evidence of flows and trapping. The ion composition data are combined with energetic proton observations from Polar and plasma observations from 1995-034 and DMSP satellites to examine the spatial and temporal extent and plasma characteristics of the cusp during a persistent northward IMF condition. The composition data is …
A New, Temporarily Confined Population In The Polar Cap During The August 27, 1996 Geomagnetic Field Distortion Period, Jiasheng Chen, Theodore A. Fritz, Robert B. Sheldon, Harlan E. Spence, Walther N. Spjeldvik, Joseph F. Fennell, Stefano Livi
A New, Temporarily Confined Population In The Polar Cap During The August 27, 1996 Geomagnetic Field Distortion Period, Jiasheng Chen, Theodore A. Fritz, Robert B. Sheldon, Harlan E. Spence, Walther N. Spjeldvik, Joseph F. Fennell, Stefano Livi
Physics & Astronomy
On August 27, 1996, a two-hour energetic heavy ion event (∼1 MeV) was detected at 8:25 UT at apogee (∼9 Re and an invariant latitude of ∼80°), by the Charge and Mass Magnetospheric Ion Composition Experiment onboard POLAR. The event, with a maximum spin averaged peak flux of ∼150 particles/(cm²-sr-s-MeV), showed three local peaks corresponding to three localized regions; the ion pitch angle distributions in the three regions were different from an isotropic distribution and different from each other. No comparable flux was observed by the WIND spacecraft. The appearance of lower energy He++ and O > +2 during the event …
First Energetic Neutral Atom Images From Polar, M. G. Henderson, G. D. Reeves, Harlan E. Spence, R. B. Sheldon, A. M. Jorgensen, J. B. Blake, J. F. Fennell
First Energetic Neutral Atom Images From Polar, M. G. Henderson, G. D. Reeves, Harlan E. Spence, R. B. Sheldon, A. M. Jorgensen, J. B. Blake, J. F. Fennell
Physics & Astronomy
Energetic neutral atoms are created when energetic magnetospheric ions undergo charge exchange with cold neutral atoms in the Earth's tenuous extended atmosphere (the geocorona). Since they are unaffected by the Earth's magnetic field, these energetic neutrals travel away in straight line trajectories from the points of charge exchange. The remote detection of these particles provides a powerful means through which the global distribution and properties of the geocorona and ring current can be inferred. Due to its 2 × 9 RE polar orbit, the Polar spacecraft provides an excellent platform from which to observe ENAs because it spends much of …
Recurrent Geomagnetic Storms And Relativistic Electron Enhancements In The Outer Magnetosphere: Istp Coordinated Measurements, D. N. Baker, X. Li, N. Turner, J. H. Allen, L. F. Bargatze, J. B. Blake, R. B. Sheldon, Harlan E. Spence, R. D. Belian, G. D. Reeves, S. G. Kanekal, B. Klecker
Recurrent Geomagnetic Storms And Relativistic Electron Enhancements In The Outer Magnetosphere: Istp Coordinated Measurements, D. N. Baker, X. Li, N. Turner, J. H. Allen, L. F. Bargatze, J. B. Blake, R. B. Sheldon, Harlan E. Spence, R. D. Belian, G. D. Reeves, S. G. Kanekal, B. Klecker
Physics & Astronomy
New, coordinated measurements from the International Solar-Terrestrial Physics (ISTP) constellation of spacecraft are presented to show the causes and effects of recurrent geomagnetic activity during recent solar minimum conditions. It is found using WIND and POLAR data that even for modest geomagnetic storms, relativistic electron fluxes are strongly and rapidly enhanced within the outer radiation zone of the Earth's magnetosphere. Solar wind data are utilized to identify the drivers of magnetospheric acceleration processes. Yohkoh solar soft X-ray data are also used to identify the solar coronal holes that produce the high-speed solar wind streams which, in turn, cause the recurrent …