ABSTRACT
For southward interplanetary magnetic field (IMF) during local summer, the hemispherically integrated Poynting flux estimated by FAST-satellite-derived empirical models is significantly larger for the northern hemisphere (NH) than for the southern hemisphere (SH). In order to test whether the difference is statistically significant, the model uncertainties have been estimated by dividing the data sets for each hemisphere into two nonintersecting sets, and separately constructing the model using each of the four sets. The model uncertainty appears to be smaller than the estimated asymmetry. The asymmetry is mostly absent when the IMF is northward, except there is some evidence that it may actually reverse during local winter. The phenomena is coupled with what appears to be a more distinct two-cell convection pattern in the NH, and a possibly greater cusp contribution in the SH. All this suggests an effect of magnetosphere-ionosphere-thermosphere coupling, probably related to asymmetries in Earth's geomagnetic field.
ABSTRACT
The relaxation behavior of phase observables for different particle diffusion models is found to establish a ground for radioscience interpretations of coherent backscatter spectra. The characteristic function for a random walk process at twice the incident radiation wave number is associated with the complex amplitude of the scattered field from a medium containing refractive index fluctuations. The phase relaxation function can be connected to the evolution of the characteristic function and may describe the average regression of the scattered field from a spontaneous fluctuation undergoing turbulent mixing. This connection holds when we assume that the stochastic description of particle movements based on a diffusion model is valid. The phase relaxation function, when identified as the generalized susceptibility function of the fluctuation dissipation theorem, is related to the spectral density of the scattered field from steady-state fluctuations.
