Narrow Results

For the first time accurate measurements of electron and positron fluxes in the energy range 0.2 ÷ 10 GeV have been performed with the Alpha Magnetic Spectrometer (AMS) at altitudes of 370 ÷ 390 km in the geographic latitude interval ±51.7°. We focused on the under-cutoff lepton fluxes inside the region of the South Atlantic Anomaly (SAA), defined as region where the local magnetic field B ≤ 0.26 G.

A clear transtion region from stably-trapped flux typical of the lnner Van Allen Belts to quasi-trapped flux typical underneath the Van Allen Belts is observed in the SAA up to energies O(Gev).

The observations strongly support positrons abundance in the Inner Van Allen Belts, both in the stably trapped component and in the quasi-trapped one.

The flux maps as a function of the canonical adiabatic variables L, α_o are presented for the intervval 0.95 < L < 3, 0° < α_o < 90° for electrons (E < 10 GeV) and positrons (E < 3 GeV). The results are compared with existing data at lower energies.

The Earth's trapped radiation belts were discovered at the beginning of the space age and were immediately recognised as a considerable hazard to space missions. Consequently, considerable effort was invested in building models of the trapped proton and electron populatinos, culminating in the NASA AP-8 and AE-8 models which have been the de facto standards since the seventies. The CRRES mission has demonstrated that the trapped radiation environment is much more complex than the static environment described by the old models. Spatial and especially temporal variations were shown to be much more important that previously thought, and to require more complex models than those in use at that time. Such models are now becoming available, but they are limited in spatial or temporal coverage, and no global, dynamic, trapped radiation belt model is forthcoming. It is therefore vital to co-ordinate future modelling efforts in order to develop new standard models.

The helium isotopes were observed by Heavy Ion Telescope (HIT) onboard the TSUBASA satellite from March, 2002 to September, 2003 in the geostationary transfer orbit. The mass resolution of the HIT instrument is ~ 0.25 amu in energy range 20÷43 MeV/nucleon for helium isotopes. Helium data in the quiet periods were analyzed to obtain the spatial and temporal variation of fluxes of helium isotopes, ³He and ⁴He. From this analysis, the enhancement of ³He flux as compared with ⁴He one in low L-value was found. Both of the helium fluxes strongly fluctuated in their L-distributions in each period.

For the first time accurate measurements of electron and positron fluxes in the energy range 0.2÷10 GeV have been performed with the Alpha Magnetic Spectrometer (AMS) at altitudes of 370÷390 km in the geographic latitude interval ±51.7°. We focused on the under-cutoff lepton fluxes inside the region of the South Atlantic Anomaly (SAA), defined as region where the local magnetic field B < 0.26 G.

A clear transition region from stably-trapped flux typical of the Inner Van Allen Belts to quasi-trapped flux typical underneath the Van Allen Belts is observed in the SAA up to energies O(Gev).

The observations strongly support positrons abundance in the Inner Van Allen Belts, both in the stably trapped component and in the quasi-trapped one.

The flux maps as a function of the canonical adiabatic variables L, α₀ are presented for the interval 0.95 < L < 3, 0°< α₀ < 90° for electrons (E<10 GeV) and positrons (E<3 GeV). The results are compared with existing data at lower energies.

The Earth's trapped radiation belts were discovered at the beginning of the space age and were immediately recognised as a considerable hazard to space missions. Consequently, considerable effort was invested in building models of the trapped proton and electron populations, culminating in the NASA AP-8 and AE-8 models which have been the de facto standards since the seventies. The CRRES mission has demonstrated that the trapped radiation environment is much more complex than the static environment described by the old models. Spatial and especially temporal variations were shown to be much more important than previously thought, and to require more complex models than those in use at that time. Such models are now becoming available, but they are limited in spatial or temporal coverage, and no global, dynamic, trapped radiation belt model is forthcoming. It is therefore vital to co-ordinate future modelling efforts in order to develop new standard models.