SM53A-0398 1340h
Estimation of global distribution of large-scale field-aligned currents on the basis of ground-based magnetic data at mid-latitudes and in the polar-cap
East-west geomagnetic disturbances at middle latitudes are mainly attributed to variations of field-aligned currents. In the dark region of the polar cap where ionospheric conductivity is small and effects of ionospheric currents are negligible, geomagnetic disturbances are mainly attributed to variations of field-aligned currents as well. Therefore significant information concerning field-aligned currents can be obtained from geomagnetic data at middle latitudes and those in the polar cap. In this study, we tried to estimate global distribution of large-scale field-aligned currents from a combination of middle latitude and polar-cap geomagnetic data with a simple inversion method. The results are generally consistent with past statistical studies based on spacecraft observations on an average. In addition, this inversion method enables us to stably infer temporal variations of global distribution of field-aligned currents, which can not be obtained from spacecraft observations. Then, we will discuss characteristics of variations in the distribution of field-aligned currents during geomagnetically disturbed conditions.
SM53A-0399 1340h
Data Mining and Visulization in Empirical and Physical Radiation Belt Studies
Empirical modeling of the radiation belt faces difficulties of organizing and data-mining large amount of multi-dimensional (in energy and space) satellite observations. Physical modeling of radiation belt faces the need to visualize and understand particle behavior in the context of global magnetospheric evolution. We have developed several approaches to address these challenges. For empirical modeling of the radiation belt, we will introduce magnetospheric state-based modeling tools which can be used to data-mine space science dataset by geophysical conditions. 3D volume visualizations are used to organize multi-satellite observed particle flux together with magnetic field shell obtained from emperical models. This makes it possible to access multi-dimensional energetic particle data, e.g. adiabatic invariant coordinates, energy, pitch angle and flux, in the context of global magnetosphere. For physical modeling of radiation belt, we will show examples of integrated view of 3D relativistic particles (electron and proton) behavior in global MHD simulations during magnetospheric substorm. Ways to quantify and visualize dependences of trapping, Shabansky orbit and lost regions of particles on initial particle pitch angle and location will be discussed.
SM53A-0400 1340h
The CISM Data Explorer
We introduce the CISM Data Explorer: a collection of data, models, and tools for analysis and visualization, to be used by space physics researchers and students. It relies heavily on well--documented programs and examples written in OpenDX, Octave, Perl, C, and FORTRAN. This project began in response to a need to simplify model (both empirical and numerical) and data (both measurements and model output) exchange between CISM group members. The CISM\_DX package is a community--developed collection of (1) Code for side--by--side visualization and analysis of the output of space physics numerical models; (2) Data sets put into a standard file format and form, and provided with code for display in IDL, Matlab, Octave, and OpenDX; (3) Tools, together with examples of their use, for space physics research, including coordinate transformation codes, and scripts that transforms data from many data providers into a standard file format and form; (4) Code for running the CISM Forecast model and code for carrying out the validation of the CISM Forecast Models using comparison data in the standard data set distributed with CISM\_DX. All of the codes in the package have been tested on computers running the Red Hat Enterprise or the Fedora Core OS, and many components can be run also on different operating systems.
SM53A-0401 1340h
Identification and Visualization of Magnetic Conjunctions for Multi-Altitude Cusp Studies
Multi-satellite studies of the magnetosphere often require that the missions be on similar magnetic field lines and/or in the same magnetospheric region. An automated process has been developed to locate such conjunctions and plot the results for inspection. New visualization tools such as SDDAS/Orbit, ViSBARD, and OVT can then be used to further study the data. These techniques are being utilized to study the cusp at low- and mid-altitudes with the DMSP and Cluster missions. The comparison of particle spectrograms from different altitudes in the cusp is important to our understanding of magnetospheric entry processes. The magnetospheric cusps act as conduits through which shocked solar wind plasma can penetrate to low altitudes. Although this plasma entry persists under all magnetospheric conditions, it is a very dynamic and complex process, strongly affected by external solar wind conditions. Low altitude measurements detect a smaller cusp that is crossed relatively quickly, while at mid altitudes the extent of the cusp is larger and the traversals much slower, blurring the distinction between temporal and spatial features and complicating conjunction studies with low altitude data. Orbit and particle data from both missions have been searched over an eight-month period for near-simultaneous cusp region crossings. This technique has found a total of 14 good quality conjunctions, two of which will be shown, making use of the visualization tools mentioned above. These conjunctions show similar complex structures that may lead to a greater understanding of particle entry in the cusp.
SM53A-0402 1340h
Magnetopause flow vortices revealed during high speed solar wind streams
Using MHD simulation and Cluster and Geotail data for high speed solar wind flow intervals in 2002, we illustrate the 3D nature of magnetopause flow vortices, and possible consequences for Earth's magnetosphere. We use observations from ACE and Wind to show characteristics of the high speed streams, including intrinsic power. Geotail and Cluster are near the magnetopause along the flanks and over the poles, respectively. GOES and LANL data are used to show the magnetospheric response. Preliminary results show that vortices on the flanks preferentially have their axes in the z-direction and are both clockwise and counterclockwise. Twisting of the magnetic field inside the vortices is crucial to finding pockets of reconnection with associated transport of particles into the magnetosphere. Eddy transport of particles can also result in turbulent regions. Energy can also be transferred across the magnetopause. Geotail observations near the magnetopause show enhanced compressional power at Pc5 frequencies, especially at the nose and on the dawn flank, both in the magnetosheath and the adjacent boundary layer. GOES 8 observations of dawn pulsations follow the trend of the compressional magnetic field fluctuations, that is higher at first and then reduced. Compressional magnetic field fluctuations may control the level of Pc5 pulsations on the dawn side. Northward IMF and high speed solar wind along with Geotail observations of magnetopause motion and MHD simulations of vortices along the flanks suggest that a Kelvin-Helmholtz (K-H) instability may contribute to transport of the compressional energy into the magnetosphere.
SM53A-0403 1340h
Immersive Visualization for Space Physics Science and Education
The development of new, relatively inexpensive immersive projection technologies (and portable inflatable fulldome theatres) have now allowed new ways of visualizing data and models. Students can be surrounded by moving imagery, allowing them to experience (and not just be told) about spatial and temporal variations, such as the dance of a Cluster orbit or the compression of field lines during a solar storm. Common misconceptions (such as the reason for the season) can be eliminated by experiences. Fulldome shows also allow a new exciting venue to bring space physics to the planetarium, a venue previously only showing starfields and planets. Now CMEs and solar storms can sweep over the public. New animation and visualization tools have been developed to maximize the experience, including riding on Cluster through an orbit while listening to the data stream from the four spacecraft. A demonstration of the immersive dome in action will be done if possible.
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