Solar Wind Turbulence Around Mars: Relation between the Energy Cascade Rate and the Proton Cyclotron Waves Activity

ROMANELLI, NORBERTO; DIBRACCIO, GINA; ANDRÉS, NAHUEL; SAHRAOUI, FOUAD; HADID, LINA Z.; HALEKAS, JASPER

The Astrophysical Journal

AAS

Año: 2020 vol. 902

The first estimation of the incompressible energy cascade rate at magnetohydrodynamic (MHD) scales in theplasma upstream of the Martian bow shock is obtained, making use of magnetic field and plasma observationsprovided by Mars Atmosphere and Volatile EvolutioN (MAVEN) over 600 orbits. In particular, the energy cascaderate is computed for events with and without proton cyclotron wave (PCW) activity, for time intervals whenMAVEN was in the solar wind with no magnetic connection to the bow shock. It is shown that the nonlinearcascade of energy at the MHD scales is slightly amplified when PCWs are present in the plasma, around theMartian perihelion. In addition, the analysis of the normalized cross helicity and residual energy for the turbulentfluctuations shows the presence of Alfvénic and non-Alfvénic fluctuations in a magnetic dominant regime for themajority of the cases.