HR: 1340h
AN: SA23A-1122    [Abstracts]
TI: Effect of atmospheric neutral density on the Earth's trapped-belt proton flux
AU: * Lodhi, M
EM: a.lodhi@ttu.edu
AF: Department of Physics Texas Tech University, MS 1051, Lubbock, TS 79409, United States
AU: Wilson, T
EM: thomas.l.wilson@nasa.gov
AF: NASA, Johnson Space Center Astromaterials and Exploration Science Directorate, 2101 NASA Parkway, Houston, TX 77058-3696, United States
AB: We have developed two models invoking a polynomial regression technique, adopted from theoretical nuclear physics, to determine the functional relationship between charged particle fluxes at minimum and maximum solar activity in the Earth's inner trapped-radiation belts. Based upon this model the charged particle flux (particularly at low energy below 350 MeV) is clearly shown to depend on solar modulation. For a given altitude the models produce two sets of curves, one for solar minimum and one for solar maximum cycles. The task at hand is to illustrate the functionality of these models. For that we are employing solar cycle 20 as base-lined in this analysis. In the case of that cycle the epoch of 1964 is used for F_10.7 maximum activity and the epoch of 1970 is used for F_10.7 minimum activity. We will show that charged-particle flux (protons in this case) versus energy in the range of 30 MeV to 350 MeV is a function of density for altitudes in the range of 350 km to 600 km. The effect of neutral atmospheric density is to spread the charged-particle (proton) flux over a bi-variant surface. The models provide the potential for evaluating charged particle (proton) intensity as a function of time through the density's dependence on the solar-cycle 10.7 cm radiation.
DE: 1630 Impacts of global change (1225)
DE: 2427 Ionosphere/atmosphere interactions (0335)
DE: 3369 Thermospheric dynamics (0358)
DE: 7536 Solar activity cycle (2162)
DE: 7974 Solar effects
SC: SPA-Aeronomy [SA]
MN: 2007 Fall Meeting