[1] Forecasting the time of arrival at Earth of interplanetary shocks following solar metric type II activity is an important first step in the establishment of an operational space weather prediction system. The quality of the forecasts is of utmost importance. The performances of the shock time of arrival (STOA) and interplanetary shock propagation models (ISPM) were previously evaluated by Smith et al. Each model predicts shock arrival time (SAT) at the Earth using real-time metric type II radio frequency drifts and coincident X-ray and optical data for input and L1 satellite observations for verification. Our evaluation of input parameters to the models showed that the accuracy of the solar metric type II radio burst observations as a measure of the initial shock velocity was compromised for those events at greater than 20°solar longitude from central meridian. The HAF model also calculates the interplanetary shock propagation imbedded in a realistic solar wind structure through which the shocks travel and interact. Standard meteorological forecast metrics are used. A variety of statistical comparisons among the three models show them to be practically equivalent in forecasting SAT. Although the HAF kinematic model performance compares favorably with ISPM and STOA, it appears to be no better at predicting SAT than ISPM or STOA. HAFv.2 takes the inhomogeneous, ambient solar wind structure into account and thereby provides a means of sorting event-driven shock arrivals from corotating interaction region (CIR) passage.
Abstract. We have assembled and tested, in real time, a space weather modeling system that starts at the Sun and extends to the Earth through a set of coupled, modular components. We describe recent efforts to improve the Hakamada-Akasofu-Fry (HAF) solar wind model that is presently used in our geomagnetic storm prediction system. We also present some results of these improvement efforts. In a related paper, Akasofu
An understanding of the transport of solar wind plasma into and throughout the terrestrial magnetosphere is crucial to space science and space weather. For non-active periods, there is little agreement on where and how plasma entry into the magnetosphere might occur. Moreover, behaviour in the high-latitude region behind the magnetospheric cusps, for example, the lobes, is poorly understood, partly because of lack of coverage by previous space missions. Here, using Cluster multi-spacecraft data, we report an unexpected discovery of regions of solar wind entry into the Earth's high-latitude magnetosphere tailward of the cusps. From statistical observational facts and simulation analysis we suggest that these regions are most likely produced by magnetic reconnection at the high-latitude magnetopause, although other processes, such as impulsive penetration, may not be ruled out entirely. We find that the degree of entry can be significant for solar wind transport into the magnetosphere during such quiet times.
Dipolarization fronts (DFs) are believed to play important roles in transferring plasmas, magnetic fluxes, and energies in the magnetotail. Using the Cluster observations in 2003, electromagnetic energy conversion at the DFs is investigated by case and statistical studies. The case study indicates strongest energy conversion at the DF. The statistical study shows the similar features that the energy of the fields can be significantly transferred to the plasmas (load, J · E > 0) at the DFs. These results are consistent with some recent simulations. Examining the electromagnetic fluctuations at the DFs, we suggest that the wave activities around the lower hybrid frequency may play an important role in the energy dissipation.
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