Measurement of the North-South asymmetry in the solar proton albedo neutron flux
Abstract
The solar proton albedo neutron flux in the range 10-2-107 eV measured by a neutron detector on board the Ogo 6 satellite was examined for north-south asymmetry. For the solar proton event of December 19, 1969, the S/N ratio of the solar proton albedo neutron rate at geomagnetic latitude λ>70° was 1.61+/-0.27 during the event, while for the November 2, 1969, event at 40°<λ<45° and altitudes ranging from 700 km to 800 km the solar proton albedo neutron rate was 0.40+/-0.10 count/s in the north and 0.00+/-0.10 count/s in the south. During the solar proton event of December 18, 1969, the N/S ratio of the solar proton albedo neutron rate at λ>70° was 1.00+/-0.26. The results are consistent with the expected N-S asymmetry in the solar proton flux. An interplanetary proton anisotropy with the interplanetary magnetic field polarity away from the sun corresponded to larger fluxes of solar proton albedo neutrons at the north polar cap than at the south, while an interplanetary proton anisotropy with the interplanetary magnetic field polarity toward the sun corresponded to larger fluxes of solar proton albedo neutrons at the south polar cap than at the north. This evidence favors the direct access of solar protons to the earth's polar caps via the merged interplanetary and geomagnetic field lines.
- Publication:
-
Journal of Geophysical Research
- Pub Date:
- April 1979
- DOI:
- 10.1029/JA084iA04p01551
- Bibcode:
- 1979JGR....84.1551I
- Keywords:
-
- Albedo;
- Interplanetary Magnetic Fields;
- Polar Caps;
- Solar Flux;
- Solar Neutrons;
- Solar Protons;
- Anisotropic Media;
- Asymmetry;
- Earth Atmosphere;
- Geomagnetism;
- Ogo-6