Simulation of VLF chorus emissions in the magnetosphere and comparison with THEMIS spacecraft data

0477290 - ÚFA 2018 RIV US eng J - Journal Article
Demekhov, A. G. - Taubenschuss, Ulrich - Santolík, Ondřej
Simulation of VLF chorus emissions in the magnetosphere and comparison with THEMIS spacecraft data.
Journal of Geophysical Research-Space Physics. Roč. 122, č. 1 (2017), s. 166-184. ISSN 2169-9380. E-ISSN 2169-9402
R&D Projects: GA MŠMT(CZ) LH15304
Grant - others:AV ČR(CZ) AP1401
Program: Akademická prémie - Praemium Academiae
Institutional support: RVO:68378289
Keywords : VLF chorus * THEMIS data * numerical simulations
OECD category: Fluids and plasma physics (including surface physics)
Impact factor: 2.752, year: 2017
http://onlinelibrary.wiley.com/doi/10.1002/2016JA023057/full

We present results of numerical simulations of VLF chorus emissions based on the backward wave oscillator model and compare them with Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft data from the equatorial chorus source region on the early morning side at a radial distance of 6 Earth radii. Specific attention is paid to the choice of simulation parameters based on experimental data. We show that with known parameters of the geomagnetic field, plasma density, and the initial wave frequency, one can successfully reproduce individual chorus elements in the simulation. In particular, the measured growth rate, wave amplitude, and frequency drift rate are in agreement with observed values. The characteristic interval between the elements has a mismatch of factor 2. The agreement becomes perfect if we assume that the inhomogeneity scale of the magnetic field along the field line is half of that obtained from the T96 model. Such an assumption can be justified since the T96 model does not fit well for the time of chorus observations, and there is a shear in the observed field which indicates the presence of local currents.
Permanent Link: http://hdl.handle.net/11104/0273673