Radial diffusion of inner-zone protons: Observations and variational analysis

Omnidirectional proton intensities (E ≈ 9-310 MeV) have been measured in seven energy channels by means of instruments on board the satellite OV1-19 (1969-25C). Unidirectional spectra representative of the time interval March–November 1969 (a period near solar maximum) have been constructed from the data by standard methods. The results enable one to construct the distribution functionf(M, L) at vanishing second invariant J for 1.18 ≤ L ≤ 2. The profiles of f(M, L) thus obtained are manipulated by a new variational method to yield normalization parameters for the radial diffusion coefficients DLL(m) and DLL(e), caused, respectively, by magnetic and electrostatic impulses of magnetospheric extent. One typically obtains DLL ∼ [7 × 10−9 + 1 × 10−10 × (γM0/M)²]L10 day−1 as the best two-parameter fit to DLL ≡ DLL(m) + DLL(e), where M0 ≡ 1 GeV/G and γ is the ratio of relativistic mass (m) to rest mass (m0).