Model‐Based Inversion of Auroral Processes

Semeter, J. L.; Zettergren, M.

doi:10.1002/9781118704417.ch25

Cited by 2 publications

(3 citation statements)

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“…Thus this flux has only a minor effect on N e at patch altitudes. These responses are expected for soft electron fluxes in the 𝐴𝐴 𝐴 1 keV range (Semeter & Zettergren, 2014), and are both consistent with observed behaviors (Figure 6). Lastly, after the source is removed, F-region densities return to their initial state in ∼15 min.…”

Section: Numerical Modeling Of Patch Formationsupporting

confidence: 89%

“…Figure 6 showed that the precipitation increased plasma production below 300 km, while simultaneously elevating T e throughout the ionosphere. These effects are the expected responses to an intense flux of soft electrons (≲200 eV) associated with Alfvénic particle acceleration (Semeter & Zettergren, 2014). An important observation is that the introduction of soft precipitation did not increase the peak patch density at ∼300 km.…”

Section: Discussionmentioning

confidence: 99%

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Auroral Heating of Plasma Patches Due to High‐Latitude Reconnection

et al. 2021

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Magnetic reconnection represents a fundamental mode of energy transfer into and out of the geospace system. Many phenomena of the polar ionosphere may be directly traced to reconnection, including the formation of fast flow channels (Zou et al., 2015), poleward moving auroral forms (Oksavik et al., 2004), poleward boundary intensifications (PBI's) along the nightside separatrix (De la Beaujardiere et al., 1994;Zou et al., 2016), and ionospheric upflow in the cusp (Strangeway et al., 2000) and nightside auroral regions (Semeter et al., 2003). From an energy perspective, the merging of the solar wind and magnetosphere constitutes a magnetospheric generator, establishing the electric fields that drive complex convection patterns in the ionosphere. For periods of southward interplanetary magnetic field (IMF), observational evidence suggests that, on average, there is a balance between magnetopause reconnection on the dayside and magnetotail reconnection on the nightside (Dungey, 1961). When the IMF is northward directed, reconnection occurs differently from the southward IMF. Regions that are favorable to reconnection shift from the dayside magnetopause to the lobe magnetic field lines poleward of the cusps (Gosling et al., 1991). The formation of reverse convection cells, multi-cell convection patterns, and soft discrete arcs in the polar cap are some of the consequences that arise due to the reversal in orientation of the IMF B z component from negative (southward) to positive (northward) (

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Section: Numerical Modeling Of Patch Formationsupporting

confidence: 89%

Section: Discussionmentioning

confidence: 99%

Auroral Heating of Plasma Patches Due to High‐Latitude Reconnection

et al. 2021

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“…The other primary ground‐based method for determining the energy flux and characteristic energy of precipitating auroral electrons is through optical observations. Determining optical emissions using an incident electron flux has recently been reviewed by Lanchester and Gustavsson [] and Semeter and Zettergren []. Dalgarno et al [] established that the intensity of the first negative emission band for

{normalN}_{2}^{+}

at 427.8 nm was proportional to the incident energy of an electron beam and thus could be used as a proxy for the energy flux of precipitating auroral electrons.…”

Section: Introductionmentioning

confidence: 99%

An investigation comparing ground‐based techniques that quantify auroral electron flux and conductance

et al. 2015

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We present three case studies that examine optical and radar methods for specifying precipitating auroral flux parameters and conductances. Three events were chosen corresponding to moderate nonsubstorm auroral activity with 557.7 nm intensities greater than 1kR. A technique that directly fits the electron number density from a forward electron transport model to alternating code incoherent scatter radar data is presented. A method for determining characteristic energy using neutral temperature observations is compared against estimates from the incoherent scatter radar. These techniques are focused on line‐of‐sight observations that are aligned with the local geomagnetic field. Good agreement is found between the optical and incoherent scatter radar methods for estimates of the average energy, energy flux, and conductances. The Pedersen conductance predicted by Robinson et al. (1987) is in very good agreement with estimates calculated from the incoherent scatter radar observations. However, we present an updated form of the relation by Robinson et al. (1987), ΣH/ΣP=0.57〈E〉0.53, which was found to be more consistent with the incoherent scatter radar observations. These results are limited to similar auroral configurations as in these case studies. Case studies are presented that quantify auroral electron flux parameters and conductance estimates which can be used to specify the magnitude of energy dissipated within the ionosphere resulting from magnetospheric driving.

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Model‐Based Inversion of Auroral Processes

Cited by 2 publications

References 38 publications

Auroral Heating of Plasma Patches Due to High‐Latitude Reconnection

Auroral Heating of Plasma Patches Due to High‐Latitude Reconnection

An investigation comparing ground‐based techniques that quantify auroral electron flux and conductance

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