Energy Flux Through the Magnetopause During Flux Transfer Events in Hybrid‐Vlasov 2D Simulations

Ala‐Lahti, Matti; Pulkkinen, Tuija; Pfau‐Kempf, Yann; Grandin, Maxime; Palmroth, Minna

doi:10.1029/2022gl100079

Cited by 6 publications

(5 citation statements)

References 44 publications

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“…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.…”

Section: Introductionsupporting

confidence: 66%

“…By using the magnetic field rather than the flow field to construct the magnetopause surface, it was shown that the effect of magnetic reconnection on the dayside results in energy outflow in the form of hydrodynamic flux at X GSM > 0 and Poynting flux inflow at X GSM < 0. 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.…”

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confidence: 53%

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

Brenner,

Pulkkinen,

Al Shidi

et al. 2023

JGR Space Physics

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We present new analysis methods of 3D MHD output data from the Space Weather Modeling Framework during a simulated storm event. Earth's magnetosphere is identified in the simulation domain and divided based on magnetic topology and the bounding magnetopause definition. Volume energy contents and surface energy fluxes are analyzed for each subregion to track the energy transport in the system as the driving solar wind conditions change. Two energy pathways are revealed, one external and one internal. The external pathway between the magnetosheath and magnetosphere has magnetic energy flux entering the lobes and escaping through the closed field region and is consistent with previous work and theory. The internal pathway, which has never been studied in this manner, reveals magnetically dominated energy recirculating between open and closed field lines. The energy enters the lobes across the dayside magnetospheric cusps and escapes the lobes through the nightside plasmasheet boundary layer. This internal circulation directly controls the energy content in the lobes and the partitioning of the total energy between lobes and closed field line regions. Qualitative analysis of four‐field junction neighborhoods indicate the internal circulation pathway is controlled via the reconnection X‐line(s), and by extension, the interplanetary magnetic field orientation. These results allow us to make clear and quantifiable arguments about the energy dynamics of Earth's magnetosphere, and the role of the lobes as an expandable reservoir that cannot retain energy for long periods of time but can grow and shrink in energy content due to mismatch between incoming and outgoing energy flux.

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Section: Introductionsupporting

confidence: 66%

contrasting

confidence: 53%

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

Brenner,

Pulkkinen,

Al Shidi

et al. 2023

JGR Space Physics

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“…In this study, β * = 0.1 is utilized to define the 3‐D magnetopause, consistent with Ala‐Lahti et al. (2022). (b) Views of the magnetopause from the direction of sunlight.…”

Section: Simulation Resultsmentioning

confidence: 84%

Three‐Dimensional Global Hybrid Simulations of Mercury's Disappearing Dayside Magnetosphere

Guo,

Lu,

et al. 2023

JGR Planets

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An important discovery of MESSENGER is the occurrence of dayside disappearing magnetosphere (DDM) events that occur when the solar wind dynamic pressure is extremely high and the interplanetary magnetic field (IMF) is both intense and southward. In this study, we investigate the DDM events at Mercury under extreme solar wind conditions using a three‐dimensional (3‐D) global hybrid simulation model. Our results show that when the solar wind dynamic pressure is 107 nPa and the magnitude of the purely southward IMF is 50 nT, most of the dayside magnetosphere disappears within 10 s after the interaction between the solar wind and the planetary magnetic field starts. During the DDM event, the ion flux is significantly enhanced at most of the planetary dayside surface and reaches its maximum value of about 1010 cm−2 s−1 at the low‐latitude surface, which is much larger than that under normal solar wind conditions. During the DDM events, the dayside bow shock mostly disappears for about 9 s and then reappears. Moreover, the time evolution of magnetopause standoff distance under different solar wind conditions is also studied. When the solar wind dynamic pressure exceeds 25 nPa and the IMF is purely southward, a part of the dayside magnetosphere disappears. Under the same IMF, the higher the solar wind dynamic pressure, the faster the magnetopause standoff distance reaches the planetary surface. When the solar wind conditions are normal (with a dynamic pressure of 8 nPa) or the IMF is purely northward, the dayside magnetosphere does not disappear. The results provide a clear physical image of DDM events from a 3‐D perspective.

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“…Physically, we may expect the magnetopause to be well approximated by an isosurface β ⋆ ∼ 1, that is, the surface where the magnetospheric magnetic pressure balances the external pressure. In practice the plasma parameters change dramatically across the magnetopause boundary, so that fixing β ⋆ to any value between 0.1 and 1.5 yields a similar result (Ala-Lahti et al, 2022;Brenner et al, 2021).…”

Section: Simulation Analysismentioning

confidence: 98%

Magnetospheric Response to a Pressure Pulse in a Three‐Dimensional Hybrid‐Vlasov Simulation

et al. 2023

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Vlasiator is a high‐performance ion‐kinetic code that is now conducting 3D hybrid‐Vlasov simulations of the global magnetosphere. We use Vlasiator to investigate the impact of a pressure pulse with southward‐oriented magnetic field on the Earth’s magnetosphere. The simulation driving parameters are comparable to conditions that have led to geomagnetic storms. Our pressure pulse simulation reproduces many physical effects, namely the expansion of the auroral oval, the development of field‐aligned currents, enhanced particle precipitation near the open/closed field line boundary, and compression of Earth’s magnetopause. This demonstrates the effectiveness of the hybrid‐Vlasov approach for moderate driving conditions. Our investigation of the time‐dependent magnetopause compression motivates a generalization of the existing theory. Specifically, we find that accounting for the finite transition time of the solar wind dynamic pressure improves the model’s description of the magnetopause oscillations.

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Energy Flux Through the Magnetopause During Flux Transfer Events in Hybrid‐Vlasov 2D Simulations

Cited by 6 publications

References 44 publications

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

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

Three‐Dimensional Global Hybrid Simulations of Mercury's Disappearing Dayside Magnetosphere

Magnetospheric Response to a Pressure Pulse in a Three‐Dimensional Hybrid‐Vlasov Simulation

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