Assessing auroral electric field variance with coherent and incoherent scatter radar

Hysell, D. L.; Michhue, G.; Nicolls, M. J.; Heinselman, C. J.; Larsen, M. F.

doi:10.1016/j.jastp.2008.10.013

Cited by 13 publications

(16 citation statements)

References 25 publications

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“…Using a small VHF coherent scatter radar imager located in Anchorage, Alaska, Bahcivan et al [2005] and Hysell et al [2008, 2009] observed Farley Buneman wave Doppler spectra that were also broadly consistent with the simulation results of Oppenheim et al [2008]. They found that the Doppler shifts and spectral widths of the echoes were approximately proportional to the cosine and sine of the flow angle, respectively, multiplied by a monotonically increasing function of the convection speed that they interpreted as representing the ion acoustic speed.…”

Section: Introductionsupporting

confidence: 65%

“…Validating the convection pattern estimates obtained from coherent scatter is essential. Bahcivan et al [2006] and Hysell et al [2008, 2009] validated against in situ electric field measurements from the JOULE and JOULE II sounding rockets. In this study, we attempt to validate against the PFISR F region line‐of‐sight ion drift measurements.…”

Section: Data Presentationmentioning

confidence: 95%

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Comparing VHF coherent scatter from the radar aurora with incoherent scatter and all‐sky auroral imagery

et al. 2012

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[1] VHF coherent scatter radar observations of an auroral substorm over Alaska are analyzed in the context of multibeam incoherent scatter plasma density and drifts data and green-line all-sky optical imagery. Coherent scatter arises from Farley Buneman waves which are excited in the E region whenever the convection electric field is greater than about 20 mV/m. Aperture synthesis radar imaging and other aspects of the methodology facilitate the precise spatial registration of the coherent scatter with coincident optical and incoherent scatter radar measurements. Discrete auroral arcs were found to separate diffuse regions of coherent backscatter and, sometimes, to align with the boundaries of those regions. At other times, auroral arcs and torches lined up adjacent to discrete, structured regions or radar backscatter. Drastic variations in the Doppler shifts of the coherent scatter from one side of the auroral forms to the other suggest the presence of field-aligned currents. An empirical formula based on previous studies but adapted to account approximately for the effects of wave turning was used to estimate the convection electric field from the moments of the coherent scatter Doppler spectra. Line-of-sight F region plasma drift measurements from the Poker Flat Incoherent Scatter Radar (PFISR) were found to be in reasonable agreement with these convection field estimates. Reasons why the empirical formulas may be expected to hold are discussed.

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Section: Introductionsupporting

confidence: 65%

Section: Data Presentationmentioning

confidence: 95%

Comparing VHF coherent scatter from the radar aurora with incoherent scatter and all‐sky auroral imagery

et al. 2012

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“…Through measuring and fitting the incoherent scatter spectrum (ISS), one can infer various ionospheric parameters. How to fit ISS to obtain the most accurate ionospheric parameters has been a subject of many studies [e.g., Hysell et al, 2009aHysell et al, , 2009bHysell et al, , 2014Zettergren et al, 2011;Milla et al, 2013]. Our current work is confined to the altitude range of about 140 to 280 km, which can be roughly considered as the F 1 region.…”

Section: Introductionmentioning

confidence: 99%

Application of particle swarm optimization method to incoherent scatter radar measurement of ionosphere parameters

Zhou

Chen

et al. 2015

JGR Space Physics

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Simultaneous derivation of multiple ionospheric parameters from the incoherent scatter power spectra in the F 1 region is difficult because the spectra have only subtle differences for different combinations of parameters. In this study, we apply a particle swarm optimizer (PSO) to incoherent scatter power spectrum fitting and compare it to the commonly used least squares fitting (LSF) technique. The PSO method is found to outperform the LSF method in practically all scenarios using simulated data. The PSO method offers the advantages of not being sensitive to initial assumptions and allowing physical constraints to be easily built into the model. When simultaneously fitting for molecular ion fraction (f m ), ion temperature (T i ), and ratio of ion to electron temperature (γ T ), γ T is largely stable. The uncertainty between f m and T i can be described as a quadratic relationship. The significance of this result is that T i can be retroactively corrected for data archived many years ago where the assumption of f m may not be accurate, and the original power spectra are unavailable. In our discussion, we emphasize the fitting for f m , which is a difficult parameter to obtain. PSO method is often successful in obtaining f m , whereas LSF fails. We apply both PSO and LSF to actual observations made by the Arecibo incoherent scatter radar. The results show that PSO method is a viable method to simultaneously determine ion and electron temperatures and molecular ion fraction when the last is greater than 0.3.

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“…In the E‐region, Tsunoda et al [2007] reported E‐field measurements from the rotation of the ion vector velocity. In addition to the ISR methods, spectral characteristics extracted from VHF coherent echoes have also been used to estimate vector E‐field [e.g., Hysell et al , 2009]. The methods used by both Tsunoda et al [2007] and [ Hysell et al 2009] are limited to high latitudes because they require very large electric field either to make neutral wind negligible or to generate plasma instability.…”

Section: Introductionmentioning

confidence: 99%

Incoherent scatter radar observation of E-region vertical electric field at Arecibo

Zhou

Morton

Huang

et al. 2011

Geophys. Res. Lett.

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We report the first spatially and temporally continuous observations of the upward electric field in the E‐region using the Arecibo incoherent scatter radar. This is achieved by employing the dual beam incoherent scatter radar measurements of ion velocity and using a theoretical ion‐neutral collision model. The derived daytime vertical electric field, from ∼105 km to 145 km, shows large height variation, as in previous nighttime rocket measurements. Assuming that the electric field along the field line is negligible, the height variation is the same as the horizontal variation at Arecibo. Although the height variation has been attributed to gravity waves in previous studies, this explanation is not consistent with the temporal characteristics in our observation. We further discuss the error sources that affect the measurement of the electric field.

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Assessing auroral electric field variance with coherent and incoherent scatter radar

Cited by 13 publications

References 25 publications

Comparing VHF coherent scatter from the radar aurora with incoherent scatter and all‐sky auroral imagery

Comparing VHF coherent scatter from the radar aurora with incoherent scatter and all‐sky auroral imagery

Application of particle swarm optimization method to incoherent scatter radar measurement of ionosphere parameters

Incoherent scatter radar observation of E-region vertical electric field at Arecibo

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