Recovery Timescales of the Dayside Martian Magnetosphere to IMF Variability

Abstract

In this work we revisit an event observed by Mars Atmosphere and Volatile Evolution MissioN in the solar wind where the interplanetary magnetic field (IMF) rotates around the Mars‐Sun axis during ∼6 min. Based on a time‐dependent LATMOS Hybrid Simulation, we determine recovery timescales of the dayside Martian magnetosphere normalized by the IMF variability timescale. Particularly, we find that such recovery timescales range between 8 s and 11 min for an ∼90° IMF rotation that lasted 50 s (observed as part of the 6‐min time interval), depending on the considered magnetospheric region. We also find that the O+ plume recovery timescales range between 40 and 120 s, taking greater values for further downstream distances (at least up to 1RM downstream from the terminator plane). This range is on the order of the magnetosheath O+ gyroperiod, showing the kinetic nature of the plume recovery process.

Formation and Evolution of the Large‐Scale Magnetic Fields in Venus' Ionosphere: Results From a Three Dimensional Global Multispecies MHD Model

“…Both the magnetosheath region and IM respond quickly to the enhanced solar wind dynamic pressure in 10s of seconds. The predicted timescale is similar to the recovery timescale of the Martian magnetosphere to interplanetary magnetic field (IMF) variations as estimated by a hybrid model (Romanelli et al, 2019). The bow shock locations bounce back a little and settle at around 1.33 R V along the subsolar point (see panel d).…”

Mars Express Observations of Cold Plasma Structures in the Martian Magnetotail

“…A future study simulating the recovery timescales of the Martian magnetotail to IMF rotations, similar to the one from Romanelli et al. (2019) for the dayside induced magnetosphere, could help explain these observations. An additional feature we notice in some cases, for instance, in orbit 16148, is comparable density values at high and low altitudes.…”

“…As we have already seen, IMF rotations are observed in the solar wind for orbit 16136 in which patchy plasma appears for SZAs as high as ∼180°, whereas the solar wind appears rather steady during orbit 16130. A future study simulating the recovery timescales of the Martian magnetotail to IMF rotations, similar to the one from Romanelli et al (2019) for the dayside induced magnetosphere, could help explain these observations. An additional feature we notice in some cases, for instance, in orbit 16148, is comparable density values at high and low altitudes.…”

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

“…This interaction starts upstream of the Martian bow shock, due to the lack of an intrinsic global planetary magnetic field and the presence of an extended hydrogen exosphere (e.g., Chaffin et al, 2015). The response of this atmospheric obstacle is significantly modified by time-dependent physical processes (e.g., Edberg et al, 2010;Jakosky et al, 2015b;Romanelli et al, 2018a), as a result of temporal variability of the planetary and solar wind properties over different timescales (e.g., Edberg et al, 2009;Modolo et al, 2012;Ma et al, 2014;Fang et al, 2015;Romanelli et al, 2018bRomanelli et al, , 2019. The seasonal variability of the Martian hydrogen exosphere has been identified by several spacecraft (Bhattacharyya et al, 2015;Chaffin et al, 2014;Clarke et al, 2014Clarke et al, , 2017Halekas et al, 2017;Halekas, 2017).…”