Solar Illumination Control of the Polar Wind

Maes, Lukas; Maggiolo, Romain; Keyser, Johan De; André, Mats; Eriksson, Anders; Haaland, Stein; Li, Kun; Poedts, Stefaan

doi:10.1002/2017ja024615

Cited by 6 publications

(9 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…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%

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

Self Cite

View full text Add to dashboard Cite

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.

show abstract

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

Self Cite

View full text Add to dashboard Cite

show abstract

“…The outflow increased to a maximum of 2.7 × 10 26 /s during the peak phase of the storm that they investigated. Maes et al (2017) observed a strong dependence of the ion velocity and density on the solar zenith angle. Li et al (2013) have investigated the transport of cold ions between the polar cap ionosphere and the plasma sheet.…”

Section: Wake Effects and Ion Outflowmentioning

confidence: 94%

“…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%

Results of the Electron Drift Instrument on Cluster

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…Heating due to solar illumination increases the ambipolar electric field that enables the polar wind outflow. The dependence of the outflow on solar zenith angle (SZA) is seen in both simulations (Glocer et al, , ) and observations (Abe et al, ; Kitamura et al, ; Maes et al, ; Su et al, ). Daily and seasonal changes in the geomagnetic dipole tilt angle modulate illumination over the source region of the polar wind and consequently modulate the polar wind.…”

Section: Introductionmentioning

confidence: 89%

“…André et al (2015) extended the data to cover most parts of the solar cycle 23. These data have been used in several studies (e.g., Haaland et al, 2012Haaland et al, , 2015Li et al, 2012Li et al, , 2013Li et al, , 2017Maes et al, 2017).…”

Section: 1029/2018ja025819mentioning

confidence: 99%

Estimating the Kinetic Energy Budget of the Polar Wind Outflow

Wei

Haaland

et al. 2018

JGR Space Physics

Self Cite

View full text Add to dashboard Cite

Ionospheric outflow from the polar cap through the polar wind plays an important role in the evolution of the atmosphere and magnetospheric dynamics. Both solar illumination and solar wind energy input are known to be energy sources of the polar wind. However, observational studies of the energy transfer from these two energy sources to the polar wind are difficult. Because of their low energy, polar wind ions are invisible to regular ion detectors onboard a positively charged spacecraft. Using a new technique that indirectly measures these low‐energy ions, we are able to estimate the energy budget of the polar wind. Our results show that solar illumination provides about 107 W of the kinetic energy of the polar wind, in addition to the energy transferred from the solar wind with a maximum rate of about 108 W. The energy transfer efficiency of solar illumination to the kinetic energy of the polar wind is about 6 to 7 orders of magnitude lower than that of the solar wind. Moreover, daily and seasonal changes in the orientation of the geomagnetic dipole axis control solar illumination over the polar cap, modulating both energies of the polar wind and energy transfer efficiencies from the two energy sources.

show abstract

Solar Illumination Control of the Polar Wind

Cited by 6 publications

References 51 publications

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

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

Results of the Electron Drift Instrument on Cluster

Estimating the Kinetic Energy Budget of the Polar Wind Outflow

Contact Info

Product

Resources

About