Observations of sub-iron (Sc-Cr) to iron (Fe) abundance ratios in the low energy (30-300 MeV/N) galactic cosmic rays in Spacelab-3 experiment and their implications

Abstract

The Spacelab-3 cosmic ray experiment Anuradha was used to measure the sub-iron (Sc-Cr) to iron abundance ratios in the low energy galactic cosmic rays. Measurments made at four different depths of the detector yielded the (Sc-Cr)/Fe ratios of 0.8 to 1.2 in 30 to 300 MeV/N. These are in agreement with results from Skylab and Soyuz-6 experiments and establishes that this abundance ratio is about 1.0 inside the magnetosphere. It is seen that this abundance ratio is about a factor of two higher than values of about 0.5 measured in space crafts in interplanetary space. It is shown that the enhancement of the ratio is probably due to the geomagnetic transmission effects and the degree of ionization of the low energy Sc to Cr and Fe ions in galactic cosmic rays. Further studies are needed to fully understand the phenomena and their implications