Bibliography
Notice:
|
Found 2 entries in the Bibliography.
Showing entries from 1 through 2
2019 |
Empirical Modeling of the Geomagnetosphere for SIR and CME-Driven Magnetic Storms During geomagnetic disturbances, the solar wind arrives in the form of characteristic sequences lasting from tens of hours to days. The most important magnetic storm drivers are the coronal mass ejections (CMEs) and the slow-fast stream interaction regions (SIRs). Previous data-based magnetic field models did not distinguish between these types of the solar wind driving. In the present work we retained the basic structure of the Tsyganenko and Andreeva (2015) model but fitted it to data samples corresponding to (1) SIR-driven storms, (2) CME-driven storms preceded with a shock ahead of the CME, and (3) CME-driven storms without such shocks. The storm time dynamics of the model current systems has been represented using the parametrization method developed by Tsyganenko and Sitnov (2005), based on dynamical variables Wi, calculated from concurrent solar wind characteristics and their previous history. The database included observations of THEMIS, Polar, Cluster, Geotail, and Van Allen Probes missions during 155 storms in 1997\textendash2016. The model current systems drastically differ from each other with respect to decay rate and total current magnitudes. During SIR-induced storms, all current systems saturate, while during CME-induced disturbances, the saturation occurs only for the symmetric ring current and the tail current. The partial ring current parameters are drastically different between SIR- and CME-induced storm sets. In the case of SIR-driven storms, the total partial ring current is comparable with symmetric ring current, whereas for all CME-induced events it is nearly twice higher. The results are compared with GOES 15 magnetometer observations. Published by: Journal of Geophysical Research: Space Physics Published on: 07/2019 YEAR: 2019   DOI: 10.1029/2018JA026008 Magnetic Storms; Magnetosphere; Modeling; Solar wind; spacecraft data; Van Allen Probes |
2017 |
Empirical modeling of the quiet and storm-time geosynchronous magnetic field A dynamical empirical model of the near-geosynchronous magnetic field has been constructed, based on a recently developed RBF approach and a multi-year set of spacecraft data taken by THEMIS, Polar, Cluster, and Van Allen Probes missions including 133 geomagnetic storms in the time interval between 1996 and 2016. The model describes the field as a function of Cartesian solar-magnetic coordinates, dipole tilt angle, solar wind ram pressure, and of a set of dynamic variables representing the response of the magnetosphere to the external driving/loading during the active phase of a space weather event, followed by the internal relaxation/dissipation during the storm recovery. In terms of the disturbance level, the model\textquoterights validity range extends to intense storms with peak Sym-H values down to -150 nT. The spatial validity domain is a toroidal volume bounded by the inner (L\~4) and outer (L\~9) dipolar L-shells, which allows the model to be used for tracing field lines to magnetically map geosynchronous spacecraft locations down to low altitudes. The model has been validated on independent out-of-sample magnetic field data and compared with an earlier empirical model and GOES-15 data taken in 2012 and 2015. Published by: Space Weather Published on: 12/2017 YEAR: 2017   DOI: 10.1002/2017SW001684 geomagnetic field; geostationary orbit; Modeling; spacecraft data; Van Allen Probes |
1