Research in Support of the National Space Weather Program

Abstracts ofAwards FY2004

Below are listed Principal Investigator (PI) name,Institution, Title, and Abstract of Proposals awarded under the researchprogram in Support of the National Space Weather Program in 2004.

Keller,Kristi A. / SP Systems, Inc.

GEM:Effect of Multiple Substorms on the Buildup of the Ring Current

Thisproject will examine the conditions that lead to a buildup of the Earth's ringcurrent during magnetic storms. It will utilize the Community CoordinatedModeling Center (CCMC) at Goddard Space Flight Center to simulate thedevelopment of the ring current. The global magnetohydrodynamics (MHD)simulation models at the CCMC can be coupled to the ring current modeldeveloped by M.-C. Fok. There are three main objectives to this project. Thefirst is to determine the relative importance of multiple substorms within astorm on the ring current dynamics. The second objective is to examine howdifferent solar wind conditions can affect the buildup of the ring current. Thethird is to simulate GEM campaign events and compare to satellite data tomonitor the performance of the simulation. The Fok Ring Current Model will bedriven using magnetic fields and ionospheric potentials from MHD simulations.The first two objectives will be met using simulated solar wind data to drivethe MHD simulations so that effects of individual solar wind andpreconditioning properties can be better isolated. MHD simulations ofdipolarization events will be used to determine the relative importance ofionospheric potential and inductive electric fields on ring current dynamics.The second part of the study will vary the solar wind magnetic field and thesolar wind density to determine the relative importance of these factors on thebuildup of the ring current. The third part will use solar wind data from theACE satellite to simulate actual events and compare the results to Los Alamosgeosynchronous satellite data. The project will help provide a better understandingof the coupled nonlinear dynamical system using computer simulations. This is afundamental problem for future space weather predictions and for geospacemodeling. The study will test the ring current and MHD models that may be usedfor space weather prediction. Since the models are available to the scientificcommunity through runs on request by the Community Coordinated Modeling Center,any improvements to the models resulting from this work will be available tothe scientific community.

Merka,Jan / L-3 Communications Government Services, Inc.

SpaceWeather: Reconstruction of the Transverse Solar Wind Profile at 1 AU UsingBasic Data Assimilation Techniques

Geomagneticstorms and sudden changes of magnetospheric properties due to sudden changes insolar wind conditions affect a wide variety of systems on Earth and in orbit.For example, large geomagnetic storms can interrupt radio communications;increase pipeline and power grid currents and change high-altitude atmosphericdrag affecting low-altitude satellite orbits. Interplanetary pressure events,like interplanetary shocks compressing the magnetosphere, lead to suddenimpulses that can have a high enough rate of ground magnetic field changeproducing an adverse amount of current in technological systems. In developingan understanding how to accurately forecast the state of the Earth'smagnetosphere, solar wind plasma and interplanetary magnetic field measurementsserve as the primary input parameters to empirical and theoretical models. Currentlymodels, predictions and general science take only single-spacecraft input fromthe solar wind even though it is known that the solar wind input can be highlyasymmetrical and multiple solar wind monitors are often available.

Therefore, the authors propose to use data from all available solar windmonitors to reconstruct a more representative solar wind profile across themagnetospheric cross-section using modern, self-consistent magnetohydrodynamic(MHD) data assimilation techniques. Furthermore, they propose to comparepredictions for real magnetospheric events based on the thus developedassimilated multi-point measurements and on the currently employed single-pointupstream observations and quantify the improvements. The proposed assimilationtechnique will allow the development of better understanding of the Sun-Earthinteractions based on a more complete description of the solar wind and moreaccurate space weather predictions. The results (both method and code will bemade publicly available) will have the potential to improve the accuracy ofspace weather predictions, and also to assist the scientific community in solarwind-magnetosphere interaction studies, especially for the case of asymmetricsolar wind/IMF input conditions.

An international and multi-institutional collaboration (NASA/GSFC, NOAA/SEC,and Charles University in Prague, Czech Republic) is planned for the proposedwork.

Ridley,Aaron J. / University of Michigan Ann Arbor

SpaceWeather: Advancement and Validation of Real-Time Assimilative Mapping ofIonospheric Electrodynamics (AMIE) for Space Weather Applications

A realistic timely knowledge of the high latitude ionospheric electricpotential pattern and auroral configuration is important for both research andoperational space weather needs. This project will advance the state of the artin specification and prediction of the ionospheric electrodynamics.Specifically, a new, time-dependent, empirical model of the high latitudeelectric potential will be developed. Individual electric potential patternswill be derived using the Assimilative Mapping of Ionospheric Electrodynamics(AMIE) technique. Since 1997, over 5 million AMIE inversions which have beenperformed and these inversions will form the core of the database. The primarydata sets that have been used and will be used are measurements of thevariations in the magnetic field at the earth's surface. Additional datasources will include incoherent scatter radar data from the Sondrestrom andMillstone Hill radars and electron density data derived from ionosphericsounders. A new feature of the modeling will be the inclusion of all-sky whitelight images into real-time AMIE. This will dramatically help the real-timespecification of the auroral location, extent, and strength. In addition, itwill allow a better specification of the electric potential through theimprovement in the conductance. The AMIE technique will be improved byincorporating adaptive mesh refinement (AMR). The AMR will be controlled by thespacing of the polar geophysical data, such that in regions in which there aremultiple data sources, AMIE will resolve features to the appropriate scale.

The empirical model will include the effect of saturation of the polar cappotential drop. No current empirical model of the potential takes thesaturation effect, which occurs when the solar wind driver is exceptionallystrong, into account, and they therefore predict unrealistically large polarcap potential drops during such periods. In order to validate the empiricalmodel, an automated system in which real-time AMIE patterns are continuouslycompared to DMSP particle precipitation and electric potential data will bedeveloped. The real-time AMIE results will then be compared with the empiricalmodel. The results will be posted on a web site for public inspection.

The project also has an educational/outreach and diversity impact. A highschool science teacher from a predominantly minority region of Detroit willtake part in project, and an automated e-mail system will be set up wherebysubscribers will be notified when it is likely that aurora may be viewed thatparticular night. Teachers in the Detroit area will use this tool to helpstudents learn more about the near-Earth space environment.

Shum,C. K. / Ohio State University Research Foundation &  Bilitza, Dieter / Raytheon Technical Services Company

CollaborativeResearch: Space Weather: Wavelet Based Regional Multi-Resolution IonosphereModeling: Investigating Structure of the Equatorial Anomaly

A collaborationbetween mathematical and space scientists provides a novel data assimilationalgorithm, capable of handling temporally and spatially inhomogeneous datasets, to assemble (in a model-useful format) an extensive amount of totalelectron content (TEC) data. These data are assembled from ionosonde networks,GPS receiver networks, satellite electron density measurements, radiooccultation data, and other sources. The data are then described in amulti-resolution ionosphere model using spherical wavelet functions, and aregional description of the ionosphere in the equatorial anomaly is a primaryfocus of the model application. The methodology takes resultant ionosphericmulti-dimensional regional ionospheric maps, generated by the data assimilationand the wavelet description, and then updates the International ReferenceIonosphere (IRI) model for improved global ionospheric model accuracy. Theresearch expects to significantly improve operational predictive capability.

Vassiliadis,Dimitrios / Universities Space Research Association

SpaceWeather: Dynamics of Regional and Local High-Latitude Geomagnetic Disturbances

Thisproject will further develop a model originally funded with earlier NSF supportto a space weather model for the fluctuations of ground magnetic field. Thecurrent model is a linear dynamical model trained on historic measurementstaken by the Finnish magnetometer array, IMAGE, the geomagnetic PC index, andthe recent history of the solar wind inputs. These elements represent the stateof geomagnetic activity and of the global magnetosphere, and a measure of theenergy available through dayside magnetic reconnection. The model produces anestimate of the horizontal (2D) field at latitudes 55-90 degrees. The dynamicsof the field are approximated as oscillation and growth/decay and they aredriven by the PC index and solar wind inputs. The proposed model will betrained to predict the full 3D ground magnetic field. A similar model will beseparately developed to predict the field fluctuations in terms of the timederivatives of the magnetic field. Time derivatives are of particularimportance because geomagnetically induced currents, which can effect theelectric power distribution grid, are driven by sudden changes in the magneticfield. The models will be nonlinear, meaning that their coefficients will beparameterized by the geomagnetic activity level. The transition from linear tononlinear dynamics will increase the prediction accuracy. The effects of thesolar wind and interplanetary magnetic field (IMF) inputs on predictionaccuracy will be examined. The solar wind-magnetosphere coupling processdepends on local time as well as on latitude. Each location of the model can bedriven by a distinct solar wind/IMF input function. The proposed model candynamically adapt to changing solar wind conditions, but it is important thatit be regularly corrected by the correct present state of geomagneticconditions. Data assimilation will be used to ingest real-time geomagneticmeasurements. Because the model can be written as a filter for the local field(or its fluctuations), it will be extended to include a Kalman filter. TheKalman component will adjust the state of the model so that it rapidlyconverges on realistic conditions at the points of measurement. A dynamic modelfor the ground magnetic field has several important applications. First,understanding the geomagnetic response and its dependence on solar wind inputand the magnetospheric configuration is an important question in magnetosphericplasma physics. The model can be used as a tool to quantify this complexcoupling as a function of interplanetary conditions and the magnetosphericstate. In addition, some aspects of the model can be used as part of studenttraining on magnetospheric and ionospheric plasma physics.