Flattening of the Density Spectrum in Compressible Hall-MHD Simulations

0548646 - ASÚ 2022 RIV CH eng J - Journal Article
Montagud-Camps, Victor - Němec, F. - Šafránková, J. - Němeček, Z. - Verdini, A. - Grappin, R. - Papini, E.
Flattening of the Density Spectrum in Compressible Hall-MHD Simulations.
Atmosphere. Roč. 12, č. 9 (2021), č. článku 1162. E-ISSN 2073-4433
Institutional support: RVO:67985815
Keywords : plasma turbulence * density spectrum * solar wind
OECD category: Astronomy (including astrophysics,space science)
Impact factor: 3.110, year: 2021
Method of publishing: Open access

Observations of proton density fluctuations of the solar wind at 1 au have shown the presence of a decade-long transition region of the density spectrum above sub-ion scales, characterized by a flattening of the spectral slope. We use the proton density fluctuations data collected by the BMSW instrument on-board the Spektr-R satellite in order to delimit the plasma parameters under which the transition region can be observed. Under similar plasma conditions to those in observations, we carry out 3D compressible magnetohydrodynamics (MHD) and Hall-MHD numerical simulations and find that Hall physics is necessary to generate the transition region. The analysis of the k omega power spectrum in the Hall-MHD simulation indicates that the flattening of the density spectrum is associated with fluctuations having frequencies smaller than the ion cyclotron frequency.
Permanent Link: http://hdl.handle.net/11104/0324688