Auroral energy deposition rate, characteristic electron energy, and ionospheric parameters derived from Dynamics Explorer 1 images

Rees, M. H.; Lummerzheim, D.; Roble, R. G.; Winningham, J. D.; Craven, J. D.; Frank, L. A.

doi:10.1029/ja093ia11p12841

Cited by 68 publications

(40 citation statements)

References 21 publications

(9 reference statements)

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“…This follows the general prOcedures described by Sojka et al [1989]. The energy fluxes Were computed from the VUV images by the algorithm !~SC?bed by Rees et al [1988]. These energy fluxes were Ithm a factor of 2 of the LAPI energy fluxes, which ~tatisticallY was the same as was found by Sojka et al [1989].…”

Section: Aurorallmagerysupporting

confidence: 68%

“…In this study, two levels of conversion were considered: the frrst is the relative energy flux which conserves the auroral spatial and temporal variability, and the second is the absolute energy flux calibration. As has been noted by Sojka et al [1989] and o~hers [Rees et al, 1988], the second part is extremely difficult to do from frrst principles. The procedure used here is to obtain the relative auroral dynamics (spatial and temporal) from the images and then to scale the energy fluxes to achieve consistency with the LAPI data.…”

Section: Aurorallmagerymentioning

confidence: 99%

“…The resulting precipitation models were compared with in situ DE 2 particle measurements. Rees et al [1988] have carried out image-to-precipitation calculations and used similar in situ cross checks on the auroral precipitation. In our previous study, a particularly dynamic auroral period was chosen because it provided excellent image sensitivity.…”

Section: In'rroducnonmentioning

confidence: 99%

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Ionospheric simulation compared with Dynamics Explorer observations for November 22, 1981

Sojka¹,

Bowline²,

Schunk³

et al. 1992

J. Geophys. Res.

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Dynamics Explorer (DE) 2 electric field and particle data have been used to constrain the inputs of a time‐dependent ionospheric model (TDIM) for a simulation of the ionosphere on November 22, 1981. The simulated densities have then been critically compared with the DE 2 electron density observations. This comparison uncovers a model‐data disagreement in the morning sector trough, generally good agreement of the background density in the polar cap and evening sector trough, and a difficulty in modelling the observed polar F layer patches. From this comparison, the consequences of structure in the electric field and precipitation inputs can be seen. This is further highlighted during a substorm period for which DE 1 auroral images were available. Using these images, a revised dynamic particle precipitation pattern was used in the ionospheric model; the resulting densities were different from the original simulation. With this revised dynamic precipitation model, improved density agreement is obtained in the auroral/polar regions where the plasma convection is not stagnant. However, the dynamic study also reveals a difficulty of matching dynamic auroral patterns with static empirical convection patterns. In this case, the matching of the models produced intense auroral precipitation in a stagnation region, which, in turn, led to exceedingly large TDIM densities.

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Section: Aurorallmagerysupporting

confidence: 68%

Section: Aurorallmagerymentioning

confidence: 99%

Section: In'rroducnonmentioning

confidence: 99%

See 1 more Smart Citation

Ionospheric simulation compared with Dynamics Explorer observations for November 22, 1981

Sojka¹,

Bowline²,

Schunk³

et al. 1992

J. Geophys. Res.

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“…The multi-channel scanning photometer at Zhongshan Station was also calibrated with standard lamps during observation. Therefore, the precipitation information (the characteristic energy and the energy flux of the electronic precipitation) can be derived from multi-wavelength optical measurements (Rees and Luckey, 1974;Rees, 1988).…”

Section: Ground-based Instrumentationmentioning

confidence: 99%

The Chinese ground-based instrumentation in support of the combined Cluster/Double Star satellite measurements

Liu

et al. 2005

Ann. Geophys.

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Abstract. Ground-based observations can be used to provide substantial support for Cluster/Double Star measurements and greatly enhance the mission's scientific return. There are six Chinese ground stations involved in coordinated cluster/Double Star and ground-based instrument observations. Among them, the Chinese Zhongshan Station in Antarctica and the Yellow River Station on Svalbard are closely magnetic conjugate and are situated under the ionospheric projection of the magnetospheric cusp regions, which, combined with satellite data, provide a perfect configuration to conduct conjugate studies of cusp phenomena. In this paper we present the ground-based instrumentation at these stations, discuss the restriction which is applyed to the optical sites and present an overview of the occurrences for conjunctions of these instruments with the spacecraft. Samples of data products are given to illustrate the potential use of these instrumentations in coordination with Cluster/Double Star measurements.

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“…By comparing auroral emissions at UV wavelengths, using filter 123 W and emissions at 557.7 nm, the characteristic energy and flux of the incoming particles were derived. Lummerzheim et al then used a method developed by Rees et al (1988) to convert the energy spectra to conductance values. Lummerzheim et al (1991) did not provide any exact electron energy range; they presented a plot showing the count rate per erg cm −2 s −1 energy flux of the 123 W filter used to deduce the electron spectra.…”

Section: Introductionmentioning

confidence: 99%

Instantaneous ionospheric global conductance maps during an isolated substorm

et al. 2002

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Abstract. Data from the Polar Ionospheric X-ray Imager (PIXIE) and the Ultraviolet Imager (UVI) on board the Polar satellite have been used to provide instantaneous global conductance maps. In this study, we focus on an isolated substorm event occurring on 31 July 1997. From the PIXIE and the UVI measurements, the energy spectrum of the precipitating electrons can be derived. By using a model of the upper atmosphere, the resulting conductivity values are generated. We present global maps of how the 5 min timeaveraged height-integrated Hall and Pedersen conductivities vary every 15 min during this isolated substorm. The method presented here enables us to study the time development of the conductivities, with a spatial resolution of ∼700 km. During the substorm, a single region of enhanced Hall conductance is observed. The Hall conductance maximum remains situated between latitudes 64 and 70 corrected geomagnetic (CGM) degrees and moves eastward. The strongest conductances are observed in the pre-midnight sector at the start of the substorm expansion. Toward the end of the substorm expansion and into the recovery phase, we find the Hall conductance maximum in the dawn region. We also observe that the Hall to Pedersen conductance ratio for the regions of maximum Hall conductance is increasing throughout the event, indicating a hardening of the electron spectrum. By combining PIXIE and UVI measurements with an assumed energy distribution, we can cover the whole electron energy range responsible for the conductances. Electrons with energies contributing most to the Pedersen conductance are well covered by UVI while PIXIE captures the high energetic component of the precipitating electrons affecting the Hall conductance. Most statistical conductance models have derived conductivities from electron precipitation data below approximately 30 keV. Since the intensity of the shortest UVI-wavelengths (LBHS) decreases significantly at higherCorrespondence to: A. Aksnes (arve.aksnes@fi.uib.no) electron energies, the UVI electron energy range is more or less comparable with the energy ranges of the statistical models. By calculating the conductivities from combined PIXIE and UVI measurements to compare with the conductivities from using UVI data only, we observe significant differences in the Hall conductance. The greatest differences are observed in the early evening and the late morning sector. We therefore suggest that the existing statistical models underestimate the Hall conductance.

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Auroral energy deposition rate, characteristic electron energy, and ionospheric parameters derived from Dynamics Explorer 1 images

Cited by 68 publications

References 21 publications

Ionospheric simulation compared with Dynamics Explorer observations for November 22, 1981

Ionospheric simulation compared with Dynamics Explorer observations for November 22, 1981

The Chinese ground-based instrumentation in support of the combined Cluster/Double Star satellite measurements

Instantaneous ionospheric global conductance maps during an isolated substorm

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