Estimating the Kinetic Energy Budget of the Polar Wind Outflow

Li, Kun; Wei, Yong; Haaland, Stein; Kronberg, Elena A.; Rong, Zhaojin; Maes, Lukas; Maggiolo, Romain; André, Mats; Nilsson, Hans; Григоренко, Е. Е.

doi:10.1029/2018ja025819

Cited by 8 publications

(10 citation statements)

References 42 publications

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“…Li et al (2017) have found approximately 237,000 records of cold ion density, velocity, and particle flux ( F P = nV || ) at 1,000 km altitude. Their tracing results have been used in the study by Li et al (2018) and in this study.…”

Section: Methodsmentioning

confidence: 99%

“…The dipole tilt angle modulates the solar zenith angle (SZA) and hence the solar irradiation over the polar cap around the dipole axis. This effect has been addressed in both simulations (e.g., Barakat et al, 2015;Glocer et al, 2012;Su et al, 1998) and observations (e.g., Kitamura et al, 2011;Li et al, 2017Li et al, , 2018Maes et al, 2017). Furthermore, the dipole tilt angle also influences magnetosphere-ionosphere coupling as simulated by Cnossen and Richmond (2012).…”

Section: Introductionmentioning

confidence: 99%

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The Polar Wind Modulated by the Spatial Inhomogeneity of the Strength of the Earth's Magnetic Field

Förster

Rong

et al. 2020

JGR Space Physics

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When the geomagnetic field is weak, the small mirror force allows precipitating charged particles to deposit energy in the ionosphere. This leads to an increase in ionospheric outflow from the Earth's polar cap region, but such an effect has not been previously observed because the energies of the ions of the polar ionospheric outflow are too low, making it difficult to detect the low-energy ions with a positively charged spacecraft. In this study, we found an anticorrelation between ionospheric outflow and the strength of the Earth's magnetic field. Our results suggest that the electron precipitation through the polar rain can be a main energy source of the polar wind during periods of high levels of solar activity. The decreased magnetic field due to spatial inhomogeneity of the Earth's magnetic field and its effect on outflow can be used to study the outflow in history when the magnetic field was at similar levels.Plain Language Summary Earth, Venus, and Mars have very different atmospheres although they are thought to possess similar atmospheres about 4.5 billion years ago. One of the main reasons considered for the losses of H 2 O and O 2 is dramatic decreases in the dipole magnetic field on Venus and Mars. Although the Earth has kept its intrinsic magnetic field, there are variations in both orientation and strength. Previous observations have confirmed that atmospheric loss is controlled by the orientation of the geomagnetic dipole. However, the effect of variations in the strength of the Earth's magnetic field on atmospheric outflow has not been addressed. In this study, we have focused on the polar wind, the dominant ionospheric outflow from the polar regions. Our results reveal an anticorrelation between the outflow and the strength of the Earth's magnetic field, offering us a clue on the ionospheric and atmospheric evolution with a changing magnetic field.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Polar Wind Modulated by the Spatial Inhomogeneity of the Strength of the Earth's Magnetic Field

Förster

Rong

et al. 2020

JGR Space Physics

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“…Those lowenergy ions can gain energy through solar illumination which changes the ionospheric scale height (Maes et al 2015). However, according to Li et al (2018) the energy transfer efficiency of the solar wind is 6-7 orders of magnitude higher than the energy originating from the solar illumination. Solar illumination of the polar cap is much affected by the tilt of the geomagnetic dipole.…”

Section: Introductionmentioning

confidence: 99%

Earth atmospheric loss through the plasma mantle and its dependence on solar wind parameters

Schillings

Slapak

Nilsson

et al. 2019

Earth Planets Space

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Atmospheric loss and ion outflow play an important role in the magnetospheric dynamics and in the evolution of the atmosphere on geological timescales-an evolution which is also dependent on the solar activity. In this paper, we investigate the total O + outflow [ s −1 ] through the plasma mantle and its dependency on several solar wind parameters. The oxygen ion data come from the CODIF instrument on board the spacecraft Cluster 4 and solar wind data from the OMNIWeb database for a period of 5 years (2001-2005). We study the distribution of the dynamic pressure and the interplanetary magnetic field for time periods with available O + observations in the plasma mantle. We then divided the data into suitably sized intervals. Additionally, we analyse the extreme ultraviolet radiation (EUV) data from the TIMED mission. We estimate the O + escape rate [ions/s] as a function of the solar wind dynamic pressure, the interplanetary magnetic field (IMF) and EUV. Our analysis shows that the O + escape rate in the plasma mantle increases with increased solar wind dynamic pressure. Consistently, it was found that the southward IMF also plays an important role in the O + escape rate in contrast to the EUV flux which does not have a significant influence for the plasma mantle region. Finally, the relation between the O + escape rate and the solar wind energy transferred into the magnetosphere shows a nonlinear response. The O + escape rate starts increasing with an energy input of approximately 10 11 W.

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“…Numerous studies have employed the above technique of combining EFW and EDI measurements to study the outflow of cold ions (André et al, 2015;Engwall et al, 2008Engwall et al, , 2009Haaland et al, 2012Haaland et al, , 2015Li et al, 2012Li et al, , 2013Li et al, , 2017Li et al, , 2018Maes et al, 2017).…”

Section: Wake Effects and Ion Outflowmentioning

confidence: 99%