Investigating turbulent structure of ionospheric plasma velocity using the Halley SuperDARN radar

Abel, Gary; Freeman, M. P.; Chisham, G.; Watkins, Nicholas W.

doi:10.5194/npg-14-799-2007

Cited by 24 publications

(54 citation statements)

References 32 publications

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“…Several recent publications focused on the electric field fluctuations in the same region (Abel et al, 2006(Abel et al, , 2007Parkinson, 2006Parkinson, , 2008. Although the scaling exponents reported in these papers describe a different aspect of auroral complexity, they can be reconciled with our analysis assuming that the electric field and the emission intensity fluctuations are generated by the same physical phenomenon.…”

Section: Discussionsupporting

confidence: 64%

Collective dynamics of bursty particle precipitation initiating in the inner and outer plasma sheet

Uritsky

Donovan²,

Klimas³

et al. 2009

Ann. Geophys.

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Abstract.Using multiscale spatiotemporal analysis of bursty precipitation events in the nighttime aurora as seen by the POLAR UVI instrument, we report a set of new statistical signatures of high-and low-latitude auroral activity, signaling a strongly non-uniform distribution of dissipation mechanism in the plasma sheet. We show that small-scale electron emission events that initiate in the equatorward portion of the nighttime auroral oval (scaling mode A 1 ) have systematically steeper power-law slopes of energy, power, area, and lifetime probability distributions compared to the events that initiate at higher latitudes (mode B). The low-latitude group of events also contain a small but energetically important subpopulation of substorm-scale disturbances (mode A 2 ) described by anomalously low distribution exponents characteristic of barely stable thermodynamic systems that are prone to large-scale sporadic reorganization. The high latitude events (mode B) can be accurately described by a single set of distributions exponents over the entire range of studied scales, with the exponent values consistent with globally stable self-organized critical (SOC) behavior. The lowand high latitude events have distinct inter-trigger time statistics, and are characterized by significantly different MLT distributions. Based on these results we conjecture that the inner and outer portions of the plasma sheet are associated with two (or more) mechanisms of collective dynamics that may represent an interplay between current disruption and magnetic reconnection scenarios of bursty energy conversion in the magnetotail.

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Section: Discussionsupporting

confidence: 64%

Collective dynamics of bursty particle precipitation initiating in the inner and outer plasma sheet

Uritsky

Donovan²,

Klimas³

et al. 2009

Ann. Geophys.

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“…It has been found that the scale-free spatial structure of the ionospheric velocity fluctuations measured by the Halley SuperDARN radar between 45 km up to about 1000 km is characterised by different values of power law exponents in areas of open and closed magnetic field lines (Abel et al 2006(Abel et al , 2007. At the same time, analysing the scaling features of the electric field fluctuations on scales of 0.5-256 km at various altitudes over the auroral zone and polar cap some authors have not found significant differences (Golovchanskaya et al 2006;Golovchanskaya and Kozelov 2010), suggesting that the drivers of turbulence in the two regions probably have the same nature.…”

Section: Discussionmentioning

confidence: 99%

Observations of high-latitude geomagnetic field fluctuations during St. Patrick’s Day storm: Swarm and SuperDARN measurements

et al. 2016

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The aim of this work is to study the properties of the magnetic field's fluctuations produced by ionospheric and magnetospheric electric currents during the St. Patrick's Day geomagnetic storm (17 March 2015). We analyse the scaling features of the external contribution to the horizontal geomagnetic field recorded simultaneously by the three satellites of the Swarm constellation during a period of 13 days (13-25 March 2015). We examine the different latitudinal structure of the geomagnetic field fluctuations and analyse the dynamical changes in the magnetic field scaling features during the development of the geomagnetic storm. Analysis reveals consistent patterns in the scaling properties of magnetic fluctuations and striking changes between the situation before the storm, during the main phase and recovery phase. We discuss these dynamical changes in relation to those of the overall ionospheric polar convection and potential structures as reconstructed using SuperDARN data. Our findings suggest that distinct turbulent regimes characterised the mesoscale magnetic field's fluctuations and that some factors, which are known to influence large-scale fluctuations, have also an influence on mesoscale fluctuations. The obtained results are an example of the capability of geomagnetic field fluctuations data to provide new insights about ionospheric dynamics and ionosphere-magnetosphere coupling. At the same time, these results could open doors for development of new applications where the dynamical changes in the scaling features of the magnetic fluctuations are used as local indicators of magnetospheric conditions.

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“…In this study, the TIGER radar data were conditioned in the same way as Abel et al (2007). The results obtained, combined with those of Parkinson (2006), imply that especially for TIGER Population B, there was reasonable conformity to power law scaling from τ =8 s (and possibly less) to ∼256 min (and greater?).…”

Section: Discussion and Summarymentioning

confidence: 99%

“…Furthermore, the α-spectra quantified the variation of the scaling properties with temporal scale, whereas the complementary "rank-order multifractal spectrum" recently proposed by Chang and Wu (2008) evaluates the variation of scaling properties with event size. Abel et al (2007) reported the results of a structure function analysis of spatial fluctuations in ionospheric plasma velocities measured using the Halley SuperDARN radar. They presented a thorough discussion on the effects of data conditioning.…”

Section: Discussion and Summarymentioning

confidence: 99%

“…Conditioning in GSF analysis usually refers to, paradoxically, the rejection of the most extreme events to help stabilise the estimation of the statistical moments (Kiyani et al, 2006). SuperDARN radar fluctuations are highly conditioned to the 3 σ level by the effective Nyquist velocity of ±2-3 km s −1 (Parkinson, 2006;Abel et al, 2007).…”

Section: Data Conditioningmentioning

confidence: 99%

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Complexity in the scaling of velocity fluctuations in the high-latitude F-region ionosphere

Parkinson

2008

Ann. Geophys.

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Abstract. The temporal scaling properties of F-region velocity fluctuations, δv los , were characterised over 17 octaves of temporal scale from τ =1 s to <1 day using a new data base of 1-s time resolution SuperDARN radar measurements. After quality control, 2.9 (1.9) million fluctuations were recorded during 31.5 (40.4) days of discretionary mode soundings using the Tasmanian (New Zealand) radars. If the fluctuations were statistically self-similar, the probability density functions (PDFs) of δv los would collapse onto the same PDF using the scaling P s (δv s , τ )=τ α P (δv los , τ ) and δv s =δv los τ −α where α is the scaling exponent. The variations in scaling exponents α and multi-fractal behaviour were estimated using peak scaling and generalised structure function (GSF) analyses, and a new method based upon minimising the differences between re-scaled probability density functions (PDFs). The efficiency of this method enabled calculation of "α spectra", the temporal spectra of scaling exponents from τ =1 s to ∼2048 s. The large number of samples enabled calculation of α spectra for data separated into 2-h bins of MLT as well as two main physical regimes: Population A echoes with Doppler spectral width <75 m s −1 concentrated on closed field lines, and Population B echoes with spectral width >150 m s −1 concentrated on open field lines. For all data there was a scaling break at τ ∼10 s and the similarity of the fluctuations beneath this scale may be related to the large spatial averaging (∼100 km×45 km) employed by SuperDARN radars. For Tasmania Population B, the velocity fluctuations exhibited approximately mono fractal power law scaling between τ ∼8 s and 2048 s (34 min), and probably up to several hours. The scaling exponents were generally less than that expected for basic MHD turbulence (α=0.25), except close to magnetic dusk where they peaked towards the basic MHD value. For Population A, the scaling exponents were larger than for Population B, having values generally Correspondence to: M. L. Parkinson (m.parkinson@latrobe.edu.au) in the range expected for basic MHD and Kolmogorov turbulence (α=0.25-0.33). The α spectra exhibited complicated variations with MLT and τ which must be related to different physical processes exerting more or less influence.

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Investigating turbulent structure of ionospheric plasma velocity using the Halley SuperDARN radar

Cited by 24 publications

References 32 publications

Collective dynamics of bursty particle precipitation initiating in the inner and outer plasma sheet

Collective dynamics of bursty particle precipitation initiating in the inner and outer plasma sheet

Observations of high-latitude geomagnetic field fluctuations during St. Patrick’s Day storm: Swarm and SuperDARN measurements

Complexity in the scaling of velocity fluctuations in the high-latitude F-region ionosphere

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