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Heavy ion results from different locations on LDEF.
1Institut fur Kernphysik, Universitat Kiel, Germany.
Radiation Measurements
|November 1, 1996
Summary
Heavy ions, including oxygen and iron, were detected below Earth's magnetic cutoff. Results align across experiments, revealing distinct energy spectra and arrival directions for cosmic rays.
Area of Science:
- Space physics
- Cosmic ray physics
- Particle detection
Background:
- Measurements of heavy ions (Z=8-26) were conducted using plastic nuclear track detectors.
- Experiments were performed on NASA's Long Duration Exposure Facility (LDEF) satellite in a 28.5-degree inclination orbit at 460 km altitude.
Purpose of the Study:
- To measure and analyze the energy spectra and arrival direction distributions of heavy ions.
- To identify the origins of detected particles, distinguishing between anomalous cosmic rays and other sources.
Main Methods:
- Utilized three independent plastic nuclear track detector experiments (M0002, A0015, HIIS) on the LDEF satellite.
- Analyzed data from particles with energies below the geomagnetic cutoff energy.
Main Results:
- Consistent results were obtained from experiments at different satellite locations.
- At energies below or equal to 70 MeV/nucleon, all particle groups exhibited steeply falling energy spectra and anisotropic arrival directions.
- Detected particles were attributed to anomalous cosmic rays (Oxygen, Neon, Argon) and an unknown source (Magnesium, Silicon, Iron).
- For the Fe-group at energies greater than or equal to 70 MeV/nucleon, a flattening energy spectrum was observed.
Conclusions:
- The findings are consistent with magnetically trapped particles observed in the South Atlantic.
- The study successfully differentiated particle origins based on their elemental composition and energy spectra.