In Situ Observation of Hall Magnetohydrodynamic Cascade in Space Plasma

Riddhi Bandyopadhyay , Luca Sorriso-Valvo , Alexandros Chasapis , Petr Hellinger , William H. Matthaeus , Andrea Verdini , Simone Landi , Luca Franci , Lorenzo Matteini (1) , Barbara L. Giles , Daniel J. Gershman , Thomas E. Moore , Craig J. Pollock , Christopher T. Russell , Robert J. Strangeway , Roy B. Torbert , James L. Burch

1 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics

We present estimates of the turbulent energy-cascade rate derived from a Hall-magnetohydrodynamic (MHD) third-order law. We compute the contribution from the Hall term and the MHD term to the energy flux. Magnetospheric Multiscale (MMS) data accumulated in the magnetosheath and the solar wind are compared with previously established simulation results. Consistent with the simulations, we find that at large (MHD) scales, the MMS observations exhibit a clear inertial range dominated by the MHD flux. In the subion range, the cascade continues at a diminished level via the Hall term, and the change becomes more pronounced as the plasma beta increases. Additionally, the MHD contribution to interscale energy transfer remains important at smaller scales than previously thought. Possible reasons are offered for this unanticipated result.

Mots clés: Physics - Space Physics; Physics - Plasma Physics

Domaines: Planète et Univers [physics]

Riddhi Bandyopadhyay, Luca Sorriso-Valvo, Alexandros Chasapis, Petr Hellinger, William H. Matthaeus, et al.. In Situ Observation of Hall Magnetohydrodynamic Cascade in Space Plasma. Physical Review Letters, 2020, 124, ⟨10.1103/PhysRevLett.124.225101⟩. ⟨insu-03717010⟩