EGU22-4524
https://doi.org/10.5194/egusphere-egu22-4524
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

A link between turbulent cascade and gyrotropic pressure instabilities in compressible and magnetized fluids. 

Pauline Simon and Fouad Sahraoui
Pauline Simon and Fouad Sahraoui
  • Laboratoire de Physique des Plasmas, CNRS, Ecole polytechnique, Université Paris-Saclay, Sorbonne Université, Observatoire de Paris-Meudon, F-91128 Palaiseau Cedex, France (pauline.simon@lpp.polytechnique.fr)

In recent years, the Kolmogorov's statistical formalism of exact law that describes incompressible hydrodynamic turbulence, has been extended to compressible magnetized fluid described by isothermal or polytropic closure. Such exact laws permit an evaluation of the energy cascade rate, assumed within this formalism to be equivalent to the dissipation rate. Its estimation in the solar wind can help to better understand particle heating in such collisionless media. But previous exact laws are insufficient in a system led by pressure anisotropy. We propose a general exact law of Hall-MHD turbulence based on models with a pressure tensor that allows us to study various known equations of state as particular limits, derive a new one corresponding to the CGL (i.e., gyrotropic pressure tensor), and correlate the cascade rate to instable plasma conditions. In the incompressible MHD limit we provide a generalization of the Politano & Pouquet law to pressure-anisotropic plasmas.

How to cite: Simon, P. and Sahraoui, F.: A link between turbulent cascade and gyrotropic pressure instabilities in compressible and magnetized fluids. , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4524, https://doi.org/10.5194/egusphere-egu22-4524, 2022.

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