Slide 1

Supporting Van Allen Probes science with the TS07D magnetic field model:

Nowcasting electron intensities, global magnetic field distribution, and magnetic field ephemerisDecember 4th, 2015: Van Allen Probes SWG TeleconGrant Stephens and Sasha Ukhorskiy

#Classic vs. New Generation of Models

TS07DTS05vs.TS07D is free of restrictions intrinsic to earlier modelsThis allows for realistic topology and temporal evolution of storm-time equatorial currentsSpatial resolution of equatorial currents are bounded by available magnetometer dataThis makes it agreeable for scientific studiesSuch 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]

#Using TS07DModel link is on Van Allen Probes Science Gatewayhttp://rbspgway.jhuapl.edu/Tsyganenkos Geopack linkTS07D link, including source code, static shielding coefficients, and dynamic model coefficients

#TS07D: New data products!We will be providing several new TS07D derived data products that will be placed on the Van Allen Probes science gatewayThe model will be precomputed and written out to cubes for easier use and will eventually cover the whole Van Allen probes timespanAdditional cubes of other magnetic field derived quantities, such as the magnetic vector potential, Euler potentials, and empirical plasma pressure will be precomputedUsing 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

#TS07D: Gridded field valuesWe will provide precomputed cubes of magnetic field vectorsCubes will be in the VTK binary formatSimple tri-linear interpolation can be used to evaluate the field within the cubeFORTRAN readers and evaluators are availableMuch much faster (500-1,000 times!) than full-evaluation of the model and less error proneCubes are ~21 MB

+8-8+12-16Z-GSMX-GSMY-GSM+16+16dx=dy=dz = 0.2 RE#TS07D: Gridded magnetic vector potentialAdditional, 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

#TS07D: Gridded field values and magnetic ephemerisInitially, 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 cadenceOnce vetted, the cubes will be expanded to encompass the whole of the Van Allen probes missionWe 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 modelsWill include, B field, L*, etc

+8-8+12-16Z-GSMX-GSMY-GSM+16+16dx=dy=dz = 0.2 RE#TS07D: Nowcasting electron intensitiesUsing simple adiabatic assumptions, we have developed a 3D nowcasting model of intensities of the electron radiation beltsModel output from a variety of electron energies from RBSPICE, MagEIS, an REPT will be provided in a 3D data formatScience studies such as this are often overly simplified (dipole field approximation) or are limited in scope due to computational constraintsUtilizing precomputed magnetic field grid significantly speeds up calculations while still having a realistic magnetic field#TS07D: Nowcasting electron intensities

MagEIS 1.5-2.0 MeV spin averaged electrons##