How to improve our understanding of solar wind-magnetosphere interactions on the basis of the statistical evaluation of the energy budget in the magnetosheath?

Abstract

Solar wind (SW) quantities, referred to as coupling parameters (CPs), are often used in statistical studies devoted to the analysis of SW–magnetosphere–ionosphere couplings. Here, the CPs and their limitations in describing the magnetospheric response are reviewed. We argue that a better understanding of SW magnetospheric interactions could be achieved through estimations of the energy budget in the magnetosheath (MS), which is the interface region between the SW and magnetosphere. The energy budget involves the energy transfer between scales, energy transport between locations, and energy conversions between electromagnetic, kinetic, and thermal energy channels. To achieve consistency with the known multi-scale complexity in the MS, the energy terms have to be complemented with kinetic measures describing some aspects of ion–electron scale physics.

Estimation of the Error in the Calculation of the Pressure‐Strain Term: Application in the Terrestrial Magnetosphere

“…However, we must consider the error if we consider a more statistical approach as advocated in Vörös et al. (2023). If the value of a pressure strain term, considering the error straddles zero, we cannot conclude that there is a net energy transfer.…”

“…in Vörös et al (2023). If the value of a pressure strain term, considering the error straddles zero, we cannot conclude that there is a net energy transfer.…”

“…Because of the spatiotemporal ambiguity, it is not always apparent whether temperature increases are due to changing environments, for example, crossing into a hotter region rather than local heating. The pressure‐strain methodology (Bandyopadhyay, Matthaeus, Parashar, et al., 2020; Cassak & Barbhuiya, 2022; Chasapis et al., 2018; Del Sarto et al., 2016; Del Sarto & Pegoraro, 2018; Fadanelli et al., 2021; Matthaeus, 2021; Matthaeus et al., 2020; Pezzi et al., 2019; Vörös et al., 2023; Wang et al., 2019; Yang et al., 2022; Yang, Matthaeus, Parashar, Haggerty, et al., 2017; Yang, Matthaeus, Parashar, Wu, et al., 2017) allows the quantification of energy conversion between the internal energy of the plasma and the bulk flow. The calculation requires multi‐spacecraft velocity measurements so that the divergence and spatial gradients of the velocity field can be calculated.…”

Energy Conversion through a Fluctuation–Dissipation Relation at Kinetic Scales in the Earth’s Magnetosheath

“…This can be due to several factors, which should pertain to the different nature of fluctuations between free solar wind and magnetosheath. These multiscale processes can involve multiple conversions between electromagnetic, kinetic, and thermal energies downstream of the bow shock (Vörös et al 2021). As a technical detail, as said before, here we use the FDR to reduce the dispersion of the possible values of the fitting parameters, different from what has been done in Carbone et al (2022).…”

Acceleration of an interplanetary shock through the magnetosheath: a global hybrid simulation

“…Despite the progress made in understanding the interaction of interplanetary shocks with the geomagnetic environment, there is still much to be learned. In recent years, there has been a growing recognition that when considering the coupling of the solar wind with the magnetosphere, it is essential to take into account the interfacing role played by the magnetosheath (e.g., Vörös et al, 2023). Therefore, an important question to consider is how interplanetary shocks propagate through the magnetosheath and are modified throughout this propagation.…”