Ring Current Ion Composition during Solar Minimum and Rising Solar Activity: POLAR/CAMMICE/MICS Results
Abstract
This report shows statistical results of the ring current ion composition and its variability as a function of solar cycle and magnetospheric activity. Spin-averaged energetic particle (1-200 keV) measurements from the POLAR/CAMMICE/MICS instrument are combined with geomagnetic indices as well as solar wind and IMF 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 to the hydrogen flux, and the average energy density ranges from a few percent at solar minimum to about 10% at high solar activity time in early 1999. The O(+) flux is typically smaller than the He(+) flux, reaching comparable values only during the latter part of the period when the solar activity increased. Analogously, the energy densities of O(+) and He(+) are about equal during 1996 and 1997, whereas the O(+) energy density is about twice the He(+) energy density during the higher solar activity period in 1998 and early 1999.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 28, 2001
- Accession Number
- ADA388184
Entities
People
- Daniel N. Baker
- Joseph F. Fennell
- N. E. Turner
- N. Ganushkina
- T. I. Pulkkinen
Organizations
- The Aerospace Corporation