Ionospheric feedback instability and substorm development

Streltsov, A. V.; Pedersen, T. R.; Мишин, Е. В.; Snyder, Arnold

doi:10.1029/2009ja014961

Cited by 28 publications

(31 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Streltsov et al [] shows two examples of strong ionospheric density depletion in a localized region next to the region where it is enhanced by auroral precipitation. The significant presence of intense ULF waves in the downward current channels has also been demonstrated by a number of observations from satellites [ Paschmann et al , ; Mishin et al , ] and on the ground [ Streltsov et al , ].…”

Section: Introductionmentioning

confidence: 74%

Auroral Current and Electrodynamics Structure (ACES) observations of ionospheric feedback in the Alfvén resonator and model responses

et al. 2013

Self Cite

View full text Add to dashboard Cite

[1] The ACES-High rocket, part of the Auroral Current and Electrodynamics Structure (ACES) mission launched from Poker Flat Research Range on 29 January 2009, obtained the first in situ measurements indicative of both of the observational characteristics associated with the ionospheric feedback instability as it flew through an auroral arc and its associated return current region. ACES-High observed Alfvénic wave structures localized in areas of roughly 10 km near the boundaries of the return current region associated with the discrete auroral arc and increased electron density with a temperature characteristic of a cold ionosphere. This density enhancement is believed to be caused by the excavation of plasma from lower altitudes via the ponderomotive force produced by the ionospheric Alfvén resonator, as shown by Streltsov and Lotko (2008). While this density is lower than expected from simulations and other observations by as much as an order of magnitude, the ratio of the enhancement to the background density is in agreement with predictions. The observations made by ACES-High agree with the model results by Streltsov and Lotko (2008) but show the localized wave structures only near the boundaries of the return current region and not throughout it. This can be explained by strong small-scale magnetic field-aligned currents that are generated by the interaction between the large-scale downward current and the ionosphere at these boundaries. Finally, a new model, based on that by Streltsov and Marklund (2006), was run with only one downward current region and produced results very similar to the observations seen by ACES-High.

show abstract

Section: Introductionmentioning

confidence: 74%

Auroral Current and Electrodynamics Structure (ACES) observations of ionospheric feedback in the Alfvén resonator and model responses

et al. 2013

Self Cite

View full text Add to dashboard Cite

show abstract

“…This can create the so‐called ionospheric feedback instability (Lysak,; Lysak & Song, ; Streltsov & Lotko, , ; Sato, ; Trakhtengerts & Feldstein, ). This instability can disrupt the Pedersen currents associated with the large‐scale downward current (Streltsov et al, ), possibly leading to the conditions for substorms onset. As such, the preonset currents and their interaction with the ionosphere may play a key role in determining the onset timing and location.…”

Section: Discussionmentioning

confidence: 99%

Seasonal and Temporal Variations of Field‐Aligned Currents and Ground Magnetic Deflections During Substorms

Forsyth¹,

Shortt²,

Coxon

et al. 2018

JGR Space Physics

View full text Add to dashboard Cite

Field‐aligned currents (FACs), also known as Birkeland currents, are the agents by which energy and momentum are transferred to the ionosphere from the magnetosphere and solar wind. This coupling is enhanced at substorm onset through the formation of the substorm current wedge. Using FAC data from the Active Magnetosphere and Planetary Electrodynamics Response Experiment and substorm expansion phase onsets identified using the Substorm Onsets and Phases from Indices of the Electrojet technique, we examine the Northern Hemisphere FACs in all local time sectors with respect to substorm onset and subdivided by season. Our results show that while there is a strong seasonal dependence on the underlying FACs, the increase in FACs following substorm onset only varies by 10% with season, with substorms increasing the hemispheric FACs by 420 kA on average. Over an hour prior to substorm onset, the dayside currents in the postnoon quadrant increase linearly, whereas the nightside currents show a linear increase starting 20–30 min before onset. After onset, the nightside Region 1, Region 2, and nonlocally closed currents and the SuperMAG AL (SML) index follow the Weimer (1994, https://doi.org/10.1029/93JA02721) model with the same time constants in each season. These results contrast earlier contradictory studies that indicate that substorms are either longer in the summer or decay faster in the summer. Our results imply that, on average, substorm FACs do not change with season but that their relative impact on the coupled magnetosphere‐ionosphere system does due to the changes in the underlying currents.

show abstract

“…Many potential processes have been proposed by e.g. Nishida and Hones (1974), Rostoker and Eastman (1987), Samson (1998), Rothwell et al (1988), Lui et al (1991), Haerendel (1992), Kan (1998), and Streltsov et al (2010). Soon after the turn of the century, two prominent scenarios of substorm development emerged with different emphasis on the initial substorm onset location and the associated physical mechanism (Baker et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

Turbulent processes in the Earth's magnetotail: spectral and statistical research

et al. 2018

View full text Add to dashboard Cite

We use the magnetic field measurements from four spacecraft of the Cluster-II mission (three events from 2005 to 2015) for the analysis of turbulent processes in the Earth's magnetotail. For this study we conduct the spectral, wavelet and statistical analysis. In the framework of statistical examination, we determine the kurtosis for selected events and conduct extended self-similarity evaluation (analysis of distribution function moments of magnetic field fluctuations on different scales). We compare the highorder structure function of magnetic fluctuations during dipolarization with the isotropic Kolmogorov model and threedimensional log-Poisson model with She-Leveque parameters. We obtain power-law scaling of the generalized diffusion coefficient (the power index that varies within the range of 0.2-0.7). The obtained results show the presence of superdiffusion processes. We find the significant difference of the spectral indices for the intervals before and during the dipolarization. Before dipolarization the spectral index lies in the range from − 1.68 ± 0.05 to −2.08 ± 0.05 (∼ 5/3 according to the Kolmogorov model). During dipolarization the type of turbulent motion changes: on large timescales the turbulent flow is close to the homogeneous models of Kolmogorov and Iroshnikov-Kraichnan (the spectral index lies in the range from −2.20 to −1.53), and at smaller timescales the spectral index is in the range from −2.89 to −2.35 (the Hall-MHD model). The kink frequency is less than or close to the average value of the proton gyrofrequency.The wavelet analysis shows the presence of both direct and inverse cascade processes, which indicates the possibility of self-organization processes, as well as the presence of Pc pulsations.

show abstract

Ionospheric feedback instability and substorm development

Cited by 28 publications

References 38 publications

Auroral Current and Electrodynamics Structure (ACES) observations of ionospheric feedback in the Alfvén resonator and model responses

Auroral Current and Electrodynamics Structure (ACES) observations of ionospheric feedback in the Alfvén resonator and model responses

Seasonal and Temporal Variations of Field‐Aligned Currents and Ground Magnetic Deflections During Substorms

Turbulent processes in the Earth's magnetotail: spectral and statistical research

Contact Info

Product

Resources

About