Energy transfer across magnetopause under dawn–dusk IMFs

Abstract

A parametric study on the energy transfer of the solar wind across the magnetopause entering the magnetosphere is conducted using a global magnetohydrodynamic numerical simulation. The characteristics of the mechanical and electromagnetic energy distribution under the dawn–dusk interplanetary magnetic fields (IMFs) are investigated by analyzing magnetic reconnection and viscous effect, and compared with the radial and north–south IMFs. It is shown that (1) the interactions at the magnetopause and the transfer of energy across this boundary move in relation to the IMF orientation. (2) For the duskward IMF, the mechanical energy flow clearly enters the equatorial and low-latitude regions on the dayside, and the electromagnetic energy flow has a small inflow on the equatorial and low latitudes of the dayside. A significant energy inflow appears on the dawn side in the northern hemisphere and the dusk side in the southern hemisphere near the polar cusp. (3) The energy distribution characteristics across the magnetopause under dawn–dusk IMFs are mirror symmetric about the $$Y=0$$ Y = 0 plane. (4) For a magnetic field of 5 nT, the electromagnetic energy input under the dawn–dusk IMFs is twice as large as the mechanical energy and the electromagnetic energy under the radial IMF, which is five times as large as the electromagnetic energy during the pure northward IMF, but only half as large as the electromagnetic energy under the pure southward IMF. The mechanical energy input under dawn–dusk IMFs has the same magnitude as that under radial and north–south IMFs. The magnitude of the energy transfer rate for the dawn IMF and dusk IMF (about 3.5%) is between 1.71% for the northward IMF and 4.95% for the southward IMF, but higher than 2.22% for the radial IMF. The Akasofu-type energy-coupling formula, $$\varepsilon$$ ε , underestimates the energy input from the solar wind under $$B_{y}$$ B y dominated IMF.

Dissecting Earth's Magnetosphere: 3D Energy Transport in a Simulation of a Real Storm Event

“…These dynamics were also seen in a study by Ala-Lahti et al (2022) using a 2D version of the Vlasiator code (Palmroth et al, 2018). This is in contrast with previous studies by Lu et al (2021) and H. Zhang et al (2023) who conclude that hydrodynamic flux (there referred to as mechanical energy flux) is entering the system near the magnetopause nose. The difference arises from their choice of the magnetopause boundary definition.…”

“…(2021) and H. Zhang et al. (2023) who conclude that hydrodynamic flux (there referred to as mechanical energy flux) is entering the system near the magnetopause nose. The difference arises from their choice of the magnetopause boundary definition.…”

“…(2021), and H. Zhang et al. (2023) have also shown that the type of energy entering the system varies significantly with the radial component of the interplanetary magnetic field (IMF) and the dipole tilt. Brenner et al.…”

“…Palmroth et al (2003) and Pulkkinen (2007) showed the dependence of the amount of energy flux and energy flux content through the magnetopause on the clock angle. Hoilijoki et al (2014), Lu et al (2021), and H. Zhang et al (2023) have also shown that the type of energy entering the system varies significantly with the radial component of the interplanetary magnetic field (IMF) and the dipole tilt. Brenner et al (2021) took this a step further showing the energy flux through a full magnetopause surface including a bounding tail cutoff and a forward surface.…”

Comparison of Solar Wind Interaction with Mars and Earth: Energy Transfer

“…The continuous exploration can help to study the evolutionary history of terrestrial planets and provide a reference for studying the future Earth with a decreasing geomagnetic field. There have been many studies on energy transfer across Earth's magnetopause (e.g., Lu et al 2011Lu et al , 2013Lu et al , 2021Jing et al 2014;Zhang et al 2023b), while research on the energy transfer across the Martian MPB is rare. Ramstad et al (2017) proposed a coupling coefficient, i.e., the ratio of the power output by escaping ions to the power input by the solar wind based on MAVEN observations.…”