Magnetospheric configurations from a high‐resolution data‐based magnetic field model

Abstract

[1] We present first results of the magnetospheric magnetic field modeling, based on large sets of spacecraft data and a high-resolution expansion for the field of equatorial currents. In this approach, the field is expanded into a sum of orthogonal basis functions of different scales, capable to reproduce arbitrary radial and azimuthal variations of the geomagnetic field, including its noon-midnight and dawn-dusk asymmetries. Combined with the existing method to model the global field of Birkeland currents, the new approach offers a natural way to consistently represent the field of both the tail and symmetrical/partial ring currents. The proposed technique is particularly effective in the modeling of the inner magnetosphere, a stumbling block for the first-principle approaches. The new model has been fitted to various subsets of data from Geotail, Polar, Cluster, IMP-8, and GOES-8, GOES-9, GOES-10, and GOES-12 spacecraft, corresponding to different activity levels, solar wind IMF conditions, and storm phases. The obtained maps of the magnetic field reproduce most basic features of the magnetospheric structure, their dependence on the geomagnetic activity and interplanetary conditions, as well as characteristic changes associated with the main and recovery phases of magnetic storms.

Space Weather Effects Produced by the Ring Current Particles

“…The most recent model version (Tsyganenko and Andreeva 2015) is intended to forecast the magnetospheric magnetic field using an optimal solar wind coupling function. A very different approach is to use the large volume of magnetic field data for reproducing the detailed structure of the magnetosphere as was done within the TS07 model (Tsyganenko and Sitnov 2007). This approach is somewhat similar to the modelling of the internal geomagnetic field with higher-order harmonics in the scalar potential expansion and it is based on extensible high-resolution expansions for the field of the equatorial current sheet.…”

Outflow of low-energy O<sup>+</sup> ion beams observed during periods without substorms

“…The ion beams are observed by all Cluster spacecraft although the details are different, indicating the structures are smaller than the SC separations (a few hundred kilometers). Preliminary results of test particle simulation using Tsyganenko model (Tsyganenko and Sitnov, 2007) with a Weimer electric field (Weimer, 2001) show these ions end up in the lobe and plasma sheet (not shown). However, the results depend on the convective field, which is not measured, and require further studies.…”

LANL<sup>*</sup>V2.0: global modeling and validation

“…We have implemented the following enhancements in the new version: (1) we have removed the limitation to geosynchronous orbit and the model can now be used for a much larger region. (2) The new version is based on the improved magnetic field model by Tsyganenko and Sitnov (2005) (TS05) instead of the older model by Tsyganenko et al (2003). We have validated the model and compared our results to L * calculations with the TS05 model based on ephemerides for CRRES, Polar, GPS, a LANL geosynchronous satellite, and a virtual RBSP type orbit.…”

“…Numerically simple models such as the static Olson-Pfitzer model (Olson, 1974) have given way to dynamic, statistical models driven by solar wind and geomagnetic inputs. The models developed by Tsyganenko and colleagues are representative and are among the most widely used (Tsyganenko et al, 2003;Tsyganenko and Sitnov, 2005). The most recent version of these models (Tsyganenko and Sitnov, 2007) is also the most computationally intensive model.…”

“…The models developed by Tsyganenko and colleagues are representative and are among the most widely used (Tsyganenko et al, 2003;Tsyganenko and Sitnov, 2005). The most recent version of these models (Tsyganenko and Sitnov, 2007) is also the most computationally intensive model. At an even higher level of complexity are global magnetohydrodynamic models or physics based plasma/field model (e.g.…”