Estimation of the high-latitude topside electron heat flux using DMSP plasma density measurements

Bekerat, Hamed; Schunk, R. W.; Scherliess, L.

doi:10.1016/j.jastp.2007.03.015

Cited by 22 publications

(31 citation statements)

References 23 publications

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“…At 6300 km these values map to −1.2 × 10 9 to −3.6 × 10 9 eV cm −2 s −1 , which are an order of magnitude larger than the values used by Glocer et al [2012]. The changes in the IFM daytime topside ionospheric profiles when such large heat fluxes are added are dramatic [Bekerat et al, 2007].…”

Section: 1002/2013ja019378mentioning

confidence: 73%

“…The statistical study by Bekerat et al [2007] demonstrated that some form of heat flux into the high-latitude ionosphere usually exists. The polar cap examples presented in this paper are consistent with that conclusion.…”

Section: Discussionmentioning

confidence: 99%

“…Note these simulations must include a nonphysical downward FAC to remove the cold electron inflow and the energy flux associated with it. The IFM simulations performed by Bekerat et al [2007] add heat fluxes by imposing a temperature gradient at the upper boundary, which is a standard practice in fluid modeling of the high-latitude ionosphere [Ganguli, 1996]. Yau et al [1995] have argued that this practice is inconsistent with in situ measurements of the polar wind, however; the electron heat fluxes point upward and are associated with escaping photoelectrons.…”

Section: Discussionmentioning

confidence: 99%

“…These heat fluxes are fairly small, however. In contrast, Bekerat et al [2007] compared the ionospheric forecast model (IFM) to DMSP measurements of plasma density at 800 km and showed that without any heat flux the IFM systematically underestimated the measurements by a factor of 2 but that reasonable agreement could be achieved if heat fluxes of −5 × 10 9 to −1.5 × 10 10 eV cm −2 s −1 were assumed at the top boundary of 1500 km. At 6300 km these values map to −1.2 × 10 9 to −3.6 × 10 9 eV cm −2 s −1 , which are an order of magnitude larger than the values used by Glocer et al [2012].…”

Section: 1002/2013ja019378mentioning

confidence: 99%

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Heating of the sunlit polar cap ionosphere by reflected photoelectrons

2014

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Photoelectrons escape from the ionosphere on sunlit polar cap field lines. In order for those field lines to carry zero current without significant heavy ion outflow or cold electron inflow, field-aligned potential drops must form to reflect a portion of the escaping photoelectron population back to the ionosphere. Using a 1-D ionosphere-polar wind model and measurements from the Resolute Bay Incoherent Scatter Radar (RISR-N), this paper shows that these reflected photoelectrons are a significant source of heat for the sunlit polar cap ionosphere. The model includes a kinetic suprathermal electron transport solver, and it allows energy input from the upper boundary in three different ways: thermal conduction, soft precipitation, and potentials that reflect photoelectrons. The simulations confirm that reflection potentials of several tens of eV are required to prevent cold electron inflow and demonstrate that the flux tube integrated change in electron heating rate (FTICEHR) associated with reflected photoelectrons can reach 10 9 eV cm −2 s −1 . Soft precipitation can produce FTICEHR of comparable magnitudes, but this extra heating is divided among more electrons as a result of electron impact ionization. Simulations with no reflected photoelectrons and with downward field-aligned currents (FAC) primarily carried by the escaping photoelectrons have electron temperatures which are ∼250-500 K lower than the RISR-N measurements in the 300-600 km region; however, simulations with reflected photoelectrons, zero FAC, and no other form of heat flux through the upper boundary can satisfactorily reproduce the RISR-N data.

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Section: 1002/2013ja019378mentioning

confidence: 73%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: 1002/2013ja019378mentioning

confidence: 99%

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Heating of the sunlit polar cap ionosphere by reflected photoelectrons

2014

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“…Although [26] mention electron energies up to 400 keV, we follow [27] with a mean energy of 100 keV. The second one is a mean case with E= 10 keV.…”

Section: Influence Of the Precipitationmentioning

confidence: 99%

Impact of Energetic Electron Precipitation on the Upper Atmosphere: Nitric Monoxide

Vialatte¹,

Barthélemy²,

Lilensten³

2017

TOASCJ

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Ionospheric electron heating associated with pulsating auroras: A Swarm survey and model simulation

et al. 2017

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In this paper we report a study on the plasma signatures (electron temperature, plasma density, and field‐aligned current) of patchy pulsating auroras in the upper F region ionosphere using Swarm satellite data. Via a survey of 38 patch crossing events, we repeatedly identify a strong electron temperature enhancement associated with the pulsating aurora. On average, the electron temperature at Swarm satellite altitudes (~460 km) increases from ~2200 K at subauroral latitudes to a peak of ~3000 K within the pulsating auroral patch. This indicates that pulsating auroras may act as an important heating source for the nightside ionosphere. On the other hand, no well‐defined trend of plasma density variations associated with pulsating auroras is identified at Swarm altitudes. The field‐aligned currents within the pulsating aurora patch are mostly upward, with mean magnitudes on order of ~1 μA/m2. We then perform a numerical simulation to explore the potential mechanisms underlying the strong electron heating associated with the pulsating aurora. Via simulations we find that to account for the realistic electron temperature observation in a major portion of our events, pulsating auroras are likely accompanied by substantial magnetospheric heat fluxes around the order of ~1010 eV/cm2. We propose that such magnetospheric heat fluxes may be pertinent to one long‐hypothesized feature of pulsating auroras, namely, the coexistence of an enhanced low‐energy plasma population in magnetic flux tubes threading the pulsating aurora, in addition to the energetic electron precipitation. Via a Swarm survey we repeatedly find a strong electron temperature enhancement associated with the pulsating aurora The field‐aligned currents within pulsating auroras are moderately upward, with mean magnitudes on the order of ~1e−6 A/m2 To explain the observed electron heating, pulsating auroras are likely accompanied by magnetospheric heat fluxes around ~1E+10 eV/cm2/s.

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Estimation of the high-latitude topside electron heat flux using DMSP plasma density measurements

Cited by 22 publications

References 23 publications

Heating of the sunlit polar cap ionosphere by reflected photoelectrons

Heating of the sunlit polar cap ionosphere by reflected photoelectrons

Impact of Energetic Electron Precipitation on the Upper Atmosphere: Nitric Monoxide

Ionospheric electron heating associated with pulsating auroras: A Swarm survey and model simulation

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