Forecasting and Monitoring of Key Geospace Parameters
The relatively simple but highly-reliable method of modeling of the energetic particles in the Earth's magnetosphere has been developed. This method does not need the special distribution of the variety of specific mechanisms for particle acceleration and their losses, but needs the average time-dependent values of the main sources and losses of these particles. Dependently of the problem under investigation, we solve one or several linked particle balance equations. The coefficients, entering the equations, are found using an optimization method, providing the best fit between the forecasted and actual data. We will demonstrate how this method works for prediction of relativistic electrons at geostationary orbit, and Dst disturbances. In both cases, our method gives extremely high correlation between forecasted and actual magnitudes of the particle fluxes. For instance, we predict the Dst variation for 1-3 hour ahead with correlation coefficient between predicted and actual data to be ~0.9 and more, and predict the relativistic electron fluxes at geosynchronous orbit for one day ahead with the correlation coefficient of about 0.92. Also using the new coupling function and new geomagnetic activity index, PM, we have developed an effective method for near-real-time monitoring the key ionospheric parameters such as the cross-polar-cap potential drop and Joule heating. The computed results are compared with the AMIE model and DMSP satellite observations.
A three-dimensional unsplit magneto-hydrodynamic code with block-structured adaptive mesh in spherical coordinate
Localization of Radio Burst Sources in the Solar Atmosphere: STEREO Observations
A new technique for the localization of the radio burst sources in the corona and interplanetary medium is presented. This technique uses the property of the medium, which permits the emission to escape the source as the direct and reflected signals along two different trajectories. Since the reflected signal (echo) travels closer to the center of the sun than the direct signal, it undergoes severe refraction, attenuation, and group delay. This leads to the different arrival directions, arrival times, and intensities. Both the direct and the echo signals can be detected by a single spacecraft as a superposition, as well as by a widely separated twin spacecraft as two distinct signals. By computing the trajectories of the direct and reflected rays, their escape angles and excess path lengths are obtained. The direct and reflected emission peaks corresponding to a type III radio burst have been identified in the data obtained by the spacecraft 'A' and 'B' of the STEREO mission, which were separated from each other by 42 degrees. By comparing the computed values with the angular separation of the spacecraft, the observed intensity ratios and the time delays, the emission source of this type III event is localized for three cases: (1) the mode of emission is unknown, (2) the mode of emission is the second harmonic, and (3) the mode of emission is the fundamental. The correction due to scattering is also provided. This method has a potential to predict the arrival times and arrival locations of the space weather critical CME shocks at 1 AU.
Validation of the SWMF Magnetosphere: Fields and Particles
The Space Weather Modeling Framework has been developed at the University of Michigan to allow many independent space environment numerical models to be executed simultaneously and coupled together to create a more accurate, all-encompassing system. This work explores the capabilities of the framework when using the BATS-R-US MHD code, Rice Convection Model (RCM), the Ridley Ionosphere Model (RIM), and the Polar Wind Outflow Model (PWOM). Ten space weather events, ranging from quiet to extremely stormy periods, are modeled by the framework. All simulations are executed in a manner that mimics an operational environment where fewer resources are available and predictions are required in a timely manner. The results are compared against in-situ measurements of magnetic fields from GOES, Polar, Geotail, and Cluster satellites as well as MPA particle measurements from the LANL geosynchronous spacecraft. Various metrics are calculated to quantify performance. Results when using only two to all four components are compared to evaluate the increase in performance as new physics are included in the system.