ION-TRANSPORT AND LOSS IN THE EARTHS QUIET RING CURRENT .2. DIFFUSION AND MAGNETOSPHERE-IONOSPHERE COUPLING

We have studied the transport and loss of H+, He+, and He++ ions in the Earth's quiet time ring current (1-300 keV/e, 3-7R(E), Kp<2+, \Dst\<11, 70-degrees - 110-degrees pitchangles, all LT) comparing the standard radial diffusion model developed for the higher-energy radiation belt particles with measurements of the lower energy ring current ions in a previous paper (Sheldon and Hamilton, 1993). Large deviations of that model, which fit only 50% of the data to within a factor of 10, suggested that another transport mechanism is operating in the ring current. Here we derive a modified diffusion coefficient corrected for electric field effects on ring current energy ions that fit nearly 80% of the data to within a factor of 2. Thus we infer that electric field fluctuations from the low-latitude to midlatitude ionosphere (ionospheric dynamo) dominate the ring current transport, rather than high-latitude or solar wind fluctuations. Much of the remaining deviation may arise from convective electric field transport of the E<30 keV particles. Since convection effects cannot be correctly treated with this azimuthally symmetric model, we defer treatment of the lowest-energy ions to a another paper. We give chi2 contours for the best fit, showing the dependence of the fit upon the internal/external spectral power of the predicted electric and magnetic field fluctuations.