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Supporting Van Allen Probes science with the TS07D magnetic field model: Nowcasting electron intensities, global magnetic field distribution, and magnetic field ephemeris December 4 th, 2015: Van Allen Probes SWG Telecon Grant Stephens and Sasha Ukhorskiy
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2 Classic vs. New Generation of Models TS07DTS05vs. TS07D is free of restrictions intrinsic to earlier models This allows for realistic topology and temporal evolution of storm-time equatorial currents Spatial resolution of equatorial currents are bounded by available magnetometer data This makes it agreeable for scientific studies Such as to study storms with different solar wind drivers: CMEs [Sitnov et al. 2008] and CIRs [Sitnov et al. 2010] And different convection modes such as SMC [Stephens et al. 2013]
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3 Using TS07D Model link is on Van Allen Probes Science Gateway http://rbspgway.jhuapl.e du/ http://rbspgway.jhuapl.e du/ Tsyganenko’s Geopack link TS07D link, including source code, static shielding coefficients, and dynamic model coefficients
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4 TS07D: New data products! We will be providing several new TS07D derived data products that will be placed on the Van Allen Probes science gateway The model will be precomputed and written out to cubes for easier use and will eventually cover the whole Van Allen probes timespan Additional cubes of other magnetic field derived quantities, such as the magnetic vector potential, Euler potentials, and empirical plasma pressure will be precomputed Using these cubes, we will produce magnetic ephemeris files including the computation of L* Using these cubes and particle flux data, and making simple adiabatic assumptions, we will nowcast the electron intensities into 3D data product
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5 TS07D: Gridded field values We will provide precomputed cubes of magnetic field vectors Cubes will be in the VTK binary format Simple tri-linear interpolation can be used to evaluate the field within the cube FORTRAN readers and evaluators are available Much much faster (500-1,000 times!) than full-evaluation of the model and less error prone Cubes are ~21 MB +8 -8 +12 -16 Z-GSM X-GSM Y-GSM +16 dx=dy=dz = 0.2 RE
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6 TS07D: Gridded magnetic vector potential Additional, cubes of the magnetic vector potential will also be precomputed: allowing for efficient computation of such quantities as: The electric field And the magnetic flux Which for a drift shell defines the third adiabatic invariant Other useful magnetic field derived parameters, such as Euler potentials or force-balance plasma pressure, could also be precomputed onto cubes
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7 TS07D: Gridded field values and magnetic ephemeris Initially, magnetic and vector potential cubes will be processed for a ‘trial’ selection of events e.g. March 2013, March 2015, and June 2015 geomagnetic storms on a 10 min cadence Once vetted, the cubes will be expanded to encompass the whole of the Van Allen probes mission We will additionally provide magnetic Ephemeris files for the Van Allen Probes mission using the TS07D model This is meant to supplement the magnetic ephemeris files being produced by ECT for other models Will include, B field, L*, etc… +8 -8 +12 -16 Z-GSM X-GSM Y-GSM +16 dx=dy=dz = 0.2 RE
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8 TS07D: Nowcasting electron intensities Using simple adiabatic assumptions, we have developed a 3D nowcasting model of intensities of the electron radiation belts Model output from a variety of electron energies from RBSPICE, MagEIS, an REPT will be provided in a 3D data format Science studies such as this are often overly simplified (dipole field approximation) or are limited in scope due to computational constraints Utilizing precomputed magnetic field grid significantly speeds up calculations while still having a realistic magnetic field
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9 TS07D: Nowcasting electron intensities MagEIS 1.5-2.0 MeV spin averaged electrons
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