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Full-Text Articles in Physical Sciences and Mathematics
Energy Content Of The Stormtime Ring Current, Niescja E. Turner, D N. Baker, T I. Pulkkinen, J L. Roeder, J F. Fennell, V K. Jordanova
Energy Content Of The Stormtime Ring Current, Niescja E. Turner, D N. Baker, T I. Pulkkinen, J L. Roeder, J F. Fennell, V K. Jordanova
Physics and Astronomy Faculty Research
Given the important role the ring current plays in magnetospheric energetics, it is essential to understand its strength and evolution in disturbed times. There are currently three main methods for deducing the strength of the ring current: measuring ground magnetic perturbations, measuring high-altitude magnetic perturbations, or directly measuring ring current particles. The use of ground magnetometers is the most convenient, and many use the ground magnetometer-derived Dst index as a proxy for the ring current. Recent work suggests, however, that a substantial portion of Dst may not be caused only by the ring current but also by local induction effects …
Ring Current Ion Composition During Solar Minimum And Rising Solar Activity: Polar/Cammice/Mics Results, T I. Pulkkinen, N Yu Ganushkina, D N. Baker, Niescja E. Turner, J F. Fennell, J L. Roeder, T A. Fritz, M Grande, B Kellett, G Kettmann
Ring Current Ion Composition During Solar Minimum And Rising Solar Activity: Polar/Cammice/Mics Results, T I. Pulkkinen, N Yu Ganushkina, D N. Baker, Niescja E. Turner, J F. Fennell, J L. Roeder, T A. Fritz, M Grande, B Kellett, G Kettmann
Physics and Astronomy Faculty Research
This paper shows statistical results of the ring current ion composition and its variability as a function of solar cycle and magnetospheric activity for 3 < L < 8. Spin-averaged energetic particle (1-200 keV) measurements from Polar are combined with geomagnetic indices as well as solar wind and interplanetary observations from the Wind spacecraft during a period from September 1996 to March 1999. The statistics are performed both for time-averaged values for all periods as well as for peak flux values during geomagnetic storms (defined as Dst < -50 nT) that occurred during this period. The average O+ energy density increases by about a factor of 5 during the rising phase of the solar cycle from the minimum values in 1996, while the average values of H+ and He show variability but no consistently increasing trend. The O+ flux is small (below 10%) compared with the hydrogen flux, and the average energy density ranges from a few percent at solar minimum to ∼10% at high solar activity time in …